Hormones chemistry. The Chemistry of Love: A Scientific View

Of the many parts of the brain, for various purposes, three organs can be distinguished that work in close conjunction with each other: the pituitary gland, the hypothalamus and the pineal gland. All three of these organs occupy a fairly small volume (compared to the total volume of the brain) - however, they have a very important function: they synthesize hormones.

Life is Beautiful. The main thing is to choose the right antidepressants.

Freud was cunning when he said "Everything starts here" - and showed ... in the fly. In fact, everything begins in the brain, or in the "brain" - whoever is used to inclining this organ.

Of the many parts of the brain, for various purposes, three organs can be distinguished that work in close conjunction with each other: pituitary, hypothalamus and epiphysis. All three of these organs occupy a rather small volume (compared to the total volume of the brain) - however, they have a very important function: they synthesize hormones. These organs are one of the main glands of secretion. endocrine system. No less important glands of endocrine secretion are the adrenal glands.

Endocrine system - a system for regulating activity internal organs through hormones secreted by endocrine cells directly into the blood, or diffusing through the intercellular space into neighboring cells.

Hormones are signaling chemicals that have complex and multifaceted effects on the body. m as a whole or on certain target organs and systems. Hormones serve as regulators of certain processes in certain organs and systems.

The 1960s were marked by significant discoveries in the field of neuroscience. It was at this time that scientists became convinced that electrical discharges alone were not enough to transmit the transmission of impulses between nerve cells.

The fact is that nerve impulses pass from one cell to another in nerve endings called " synapses". It turned out, Most synapses are by no means electrical, as previously thought, but a chemical mechanism of action.

At the same time, neurotransmitters (neurotransmitters) are involved in the transmission of nerve signals - biologically active substances that are a chemical transmitter of impulses between the nerve cells of the human brain.

1. Mood: Serotonin

Serotonin is a neurotransmitter - one of the substances that are a chemical transmitter of impulses between the nerve cells of the human brain. Serotonin-responsive neurons are located almost throughout the brain.

Most of them are in the so-called "raphe nuclei" - areas of the brain stem. This is where the synthesis of serotonin occurs in the brain. In addition to the brain, a large amount of serotonin is produced by the mucous membranes of the gastrointestinal tract.

The directions of propagation of serotonin impulses from these nuclei affect many areas of both the brain and spinal cord.

It is difficult to overestimate the role that serotonin plays in the human body:

In the anterior part of the brain, under the influence of serotonin, the areas responsible for process of cognitive activity.

Serotonin entering the spinal cord positively affects motor activity and muscle tone. This state can be characterized by the phrase "I will move mountains."

And finally, the most important thing - an increase in serotonergic activity creates in the cerebral cortex feeling uplifted. For now, we will limit ourselves to just such a term, although in various combinations of serotonin with other hormones - we get the whole range of emotions of "satisfaction" and "euphoria" - but we will talk about this a little later.

Lack of serotonin, on the contrary, causes a decrease in mood and depression.

In addition to mood, serotonin is responsible for self-control or emotional stability. b (Mehlman et al., 1994). Serotonin controls the susceptibility of brain receptors to the stress hormones adrenaline and norepinephrine (which will be discussed later).

In people with low levels of serotonin, the slightest stimulus triggers an exuberant stress response. Some researchers believe that the dominance of an individual in the social hierarchy is due precisely to the high level of serotonin.

In order for serotonin to be produced in our body, two things are necessary:

dietary intake of the amino acid tryptophan - since it is it that is needed for the direct synthesis of serotonin in synapses

intake of glucose with carbohydrate food => stimulation of insulin release into the blood => stimulation of protein catabolism in tissues => increase in the level of tryptophan in the blood.

The following phenomena are directly related to these facts: bulimia and the so-called "sweet tooth syndrome".

The whole point is that serotonin can cause a subjective feeling of satiety. When food enters the body, including those containing tryptophan, the production of serotonin increases, which improves mood. The brain quickly catches the connection between these phenomena - and in case of depression (serotonin starvation), it immediately "requires" additional intake of food with tryptophan or glucose.

Surprisingly, tryptophan-rich foods are those that are almost entirely carbs, such as bread, bananas, chocolate, or net carbs like table sugar or fructose. This indirectly confirms the assertion that exists in society that sweet people / fat people are kinder than thin people.

Serotonin is metabolized in the body by monoamine oxidase-A (MAO-A) to 5-hydroxyindoleacetic acid, which is then excreted in the urine. The first antidepressants were monoamine oxidase inhibitors.

However, due to the large number side effects caused by the broad biological action of monoamine oxidase, "serotonin reuptake inhibitors" are currently used as antipepressants. These substances make it difficult to reuptake serotonin in the synapses, thereby increasing its concentration in the blood.

2. Day and night: melatonin

We have already found out that serotonin, firstly, is produced by food enriched with tryptophan and glucose, and secondly, it dulls the feeling of hunger. We found out why serotonin gives a surge of physical strength.

Serotonin has an antipode in the body - it's melatonin.. They are synthesized in the pineal gland ("pineal gland") from serotonin. The secretion of melatonin directly depends on the general level of illumination.- an excess of light inhibits its formation, and a decrease in illumination, on the contrary, increases the synthesis of melatonin.

It is under the influence of melatonin that gamma-aminobutyric acid is produced, which, in turn, inhibits the synthesis of serotonin. 70% of daily production of melatonin occurs at night.

It is melatonin synthesized in the pineal gland that is responsible for circadian rhythms.- human internal biological clock. As correctly noted, the circadian rhythm is not directly determined external causes, such as sunlight and temperature, but depends on them - since the synthesis of melatonin depends on them.

It is low light and, as a result, high production of melatonin that are the main causes of seasonal depression. Remember the emotional upsurge when a clear, fine day is issued in winter. Now you know why this happens - on this day you have a decrease in melatonin and an increase in serotonin.

I note that melatonin is not produced by itself - but from serotonin. And at the same time, he blunts his production. It is on these almost dialectical "unity and struggle of opposites" that the internal mechanism of self-regulation of circadian rhythms is arranged. That is why, in a state of depression, people suffer from insomnia - in order to fall asleep, you need melatonin, and without serotonin, you can’t get it.

3. Pleasure: dopamine

Consider another neurotransmitter - dopamine(or dopamine) - a substance of the group of phenylethylamines. It is hard to overestimate the role of dopamine in the human body - like serotonin, it acts as a neurotransmitter and hormone at the same time. Cardiac activity, motor activity, and even the gag reflex indirectly depend on it.

The hormone dopamine is produced by the adrenal medulla, and the neurotransmitter dopamine is produced by an area of the midbrain called the black body.

We are interested in the dopamine neurotransmitter. Four "dopamine pathways" are known - brain pathways in which dopamine plays the role of a carrier of a nerve impulse. One of them, the mesolimbic pathway, is thought to be responsible for producing feelings of pleasure.

Dopamine levels peak during activities such as eating and sex.

Why do we enjoy thinking about the upcoming pleasure? Why can we savor the upcoming pleasure for hours? Recent studies show that the production of dopamine begins even in the process of waiting for pleasure. This effect is similar to the pre-salivation reflex in Pavlov's dog.

Dopamine is also believed to be involved in human decision making. At least among people with impaired dopamine synthesis/transport, many have difficulty making decisions. This is due to the fact that dopamine is responsible for the "sense of reward", which often allows you to make a decision, considering this or that action at a subconscious level.

Unfortunately, neuroscience is still developing. In particular, the relatively recent 2000 Nobel Prize in Biology was awarded for discoveries in the field of "signaling in the nervous system". Therefore, to get more detailed information on neurotransmitters from the Russian-speaking Internet, on this moment does not seem possible.

4. Fear and rage: adrenaline and norepinephrine

But not all vital processes of managing the human body take place in the brain. Adrenal glands - paired endocrine glands of all vertebrates also play an important role in the regulation of its functions. It is in them that the two most important hormones are produced: adrenaline and norepinephrine.

Adrenaline is the most important hormone that implements reactions such as "fight or flight". Its secretion increases sharply in stressful conditions, borderline situations, a sense of danger, anxiety, fear, trauma, burns and shock.

Adrenaline is not a neurotransmitter, but a hormone - that is, it is not directly involved in the promotion of nerve impulses. But, having entered the blood, it causes a whole storm of reactions in the body:

Strengthens and speeds up the heartbeat

Causes vasoconstriction of muscles, abdominal cavity, mucous membranes

Relaxes the muscles of the intestines, and dilates the pupils. Yes, yes, the expression "fear has big eyes" and stories about the meetings of hunters with bears have absolutely scientific grounds.

The main task of adrenaline is to adapt the body to a stressful situation.. Adrenaline improves the functional capacity of skeletal muscles. With prolonged exposure to adrenaline, an increase in the size of the myocardium and skeletal muscles is noted. At the same time, prolonged exposure to high concentrations of adrenaline leads to increased protein metabolism, a decrease in muscle mass and strength, weight loss and exhaustion. This explains the emaciation and exhaustion in distress (stress that exceeds the adaptive capacity of the body).

Norepinephrine is a hormone and neurotransmitter. Norepinephrine also increases with stress, shock, trauma, anxiety, fear, nervous tension. Unlike epinephrine, the main action of noradrenaline is exclusively in vasoconstriction and an increase in blood pressure. The vasoconstrictive effect of norepinephrine is higher, although the duration of its action is shorter.

Both epinephrine and noradrenaline can cause tremors - that is, trembling of the limbs, chin. This reaction is especially clear in children aged 2-5 years, when a stressful situation occurs.

Immediately after determining the situation as stressful, the hypothalamus secretes corticotropin (adrenocorticotropic hormone) into the blood, which, upon reaching the adrenal glands, induces the synthesis of norepinephrine and adrenaline.

The "invigorating" effect of nicotine is provided by the release of adrenaline and noradrenaline into the blood. On average, it takes about 7 seconds after inhaling tobacco smoke for nicotine to reach the brain. In this case, there is a short-term acceleration of the heartbeat, an increase in blood pressure, an increase in breathing and an improvement in the blood supply to the brain. The accompanying release of dopamine contributes to the consolidation of nicotine addiction..

It is interesting that in different animals the ratio of cells synthesizing adrenaline and to norepinephrine varies. Noradrenocytes are very numerous in the adrenal glands of predators and are almost never found in their potential prey. For example, in rabbits and guinea pigs, they are almost completely absent. Maybe that's why the lion is the king of animals, and the rabbit is just a rabbit?

It is believed that norepinephrine is the hormone of rage, and adrenaline is the hormone of fear. Norepinephrine causes a feeling of anger, rage, permissiveness in a person. Adrenaline and norepinephrine are closely related to each other. In the adrenal glands, adrenaline is synthesized from norepinephrine.. Which once again confirms the long-known idea that the emotions of fear and hatred are related, and are generated from one another.

Without adrenal hormones, the body is "defenseless" in the face of any danger.. Numerous experiments confirm this: animals in which the adrenal medulla was removed turned out to be unable to make any stressful efforts: for example, to flee from an impending danger, defend themselves, or get food.

5. Happiness is:

In the wonderful book "Secrets of Behavior of Homo Sapiens" it is written: "The terms "joy", "happiness" and "euphoria" are commonly used to denote a pronounced uplift in mood. This subjective state is analogous to the pleasure that occurs when eating a gourmet meal after a strong hunger. Now we already know that serotonin is responsible for joy, and dopamine is responsible for pleasure. But there are two more groups of hormones, without which "happiness" was not complete.

5.1 Endogenous opiates (endorphins, enkephalins)

Firstly, this is a family of endorphins, and the most common of them is beta endorphin.

Endorphins were discovered in the 70s of the last century, when European scientists began to study the mechanisms of the analgesic effect of the Chinese acupuncture system. It was found that when drugs are introduced into the human body that block the analgesic effect of narcotic analgesics, the effect of pain relief by acupuncture disappears.

It was suggested that during acupuncture in the human body, substances are released that are chemically similar to morphine. Such substances received the conditional name "endorphins", or "internal morphines".

Similar in action to endorphins - enkephalins. Some researchers classify them as a subset of endorphins, while others classify them as a separate group of neurotransmitters. In other works, it is believed that enkephalins are a by-product of underutilized endorphins. Enkephalins have a very similar effect to endorphins. However, their pain relief is weaker and more short-lived.

Physiologically, endorphins and enkephalins have the strongest analgesic, anti-shock and anti-stress effect, they reduce appetite and reduce the sensitivity of certain parts of the central nervous system. "Blind with happiness" - to say exaggerated.

Endorphins normalize arterial pressure, respiratory rate, accelerate the healing of damaged tissues, the formation of callus in fractures. Happy people recover faster - it's a scientifically proven fact.

It is now believed that endorphins are synthesized in the pituitary and hypothalamus, and enkephalins are synthesized in the hypothalamus. Another difference between endorphins and enkephalins is that endorphins have a selective, while enkephalins have a more general inhibitory effect on the receptors of the central nervous system.

The main target of endorphins is the so-called opioid system of the body, and opioid receptors in particular. Due to their similarity to narcotic substances like morphine, endorphins and enkephalins have been called "endogenous (i.e., internal) opiates."

Psychologically, by acting on opioid receptors, both endorphins and enkephalins cause euphoria- "a form of morbidly elevated mood." Euphoria includes not only emotional changes, but also a whole range of mental and somatic sensations, feelings, due to which a positive emotional shift is achieved.

Euphoria is one of the "side effects" of dealing with stress.. After successfully overcoming loads, after getting out of a difficult situation, the body receives a "carrot", a reward in the form of positive emotions. But stress is just one of many endorphin releases. It has been experimentally established that the release of endorphins in a person is directly related to the feeling of happiness, momentary bliss.

There is an opinion that euphoria from viewing works of art, listening to music - also has an endorphin nature. The euphoria of orgasm is also endorphins, but we will talk about orgasm a little later. Another way to produce endorphins is to exercise. The reason for the popularity of sports is not only in the cult of strength, but also in the release of endorphins that occurs when the stressful load stops.

Everyone knows the classic experience with rats, when electrodes were implanted into the brain of a rat to stimulate the hypothalamus. The rat could, by pressing the pedal, actuate the electrodes. As a result of the experiment, the rat, having established a connection between the pedal and pleasure, died of thirst or exhaustion, heart-rendingly pressing the pedal. Usually this experience is cited as a classic example of drug addiction. And the mechanism of rat pleasure is the same endorphins produced in the hypothalamus under the influence of electrical discharges.

In addition to electrical stimulation of the hypothalamus, there is another way to catch the "eternal high". These are opiates: ranging from natural opium - the milky juice of unripe pods of the opium poppy, and the morphine and codeine contained in it, to synthetic heroin - which is many times stronger than morphine, and much more addictive.

The mechanism of addiction to opiates is to adapt the body to an increased concentration of morphine, by reducing the sensitivity of opioid receptors. As a result, firstly, the dose of morphine necessary to obtain "euphoria" increases, and secondly, the receptors become practically insensitive to small doses of internal endorphins.

It is significant that if a healthy person who has never used drugs is injected with the drug naloxone, which blocks opioid receptors, he sinks into depression and experiences a mental state of discomfort, akin to drug withdrawal. This once again confirms the importance of opioid receptors in a person's feeling of happiness.

By the way, addiction to morphine is manifested not only among drug addicts. Everyone knows that with age, fewer and fewer events can give a person a feeling of happiness. "Speech will become wiser, but the smile is stingy, and the New Year's dope is weaker." So, this dope is weaker precisely because of the addiction of receptors to endorphins. Therefore, it is much harder for an adult to "get drunk with happiness" than for a child.

It is believed that endogenous opiates (like cannoboids, which I will discuss below), in addition to their already described functions, perform the regulation of the "second level" - they regulate the adrenaline, dopamine, and serotonin systems. That is, these are neuroregulators that control other neuroregulators. However, I have not yet seen a detailed substantiation of this point of view in the mass literature.

5.2 Endogenous cannabinoids (anandamide)

Until recently, endogenous morphine was thought to be the only neurotransmitter that produces feelings of happy euphoria. However, in 1992, the substance "anandamide" was found in the brain, capable of imitating all the known effects of marijuana. Endogenous cannabinoids also include the substance "2-arachidonoyl-glycerol".

The purpose of endogenous cannabinoids has not yet been fully defined. In the human body, there is a whole system of cannabinoid receptors.

In 2003, it was experimentally established that endocannabinoids play an important role in eliminating negative emotions and pain associated with past experiences. At the beginning of the experiment, a certain sound was combined with a brief stimulation of the rodent's paws with a weak electric current. After a while, having heard the sound, the animal freezes in anticipation of an electric shock. If the sound is not accompanied by electric pain stimulation over and over again, it ceases to be afraid of it: the developed conditioned reflex fades away. It turns out that animals with blocked cannabinoid receptors could not free themselves from fear when the sound ceased to be combined with pain.

So, if you can't get rid of the negative memories associated with past experiences, your system is deficient in cannabinoids. Endogenous, or extragenous - it's who likes what more..

6 Falling In Love: Phenylethylamine

2-phenylethylamine (or PEA) is a neurotransmitter and neuromodulator of interpersonal energy. The allocation of REA increases emotional warmth, sympathy, sexuality.

Although phenethylamine is the initial compound for other neurotransmitters, and itself it is often released along with dopamine and serotonin however, its action in the emotional realm is one of a kind. For PEA, a specific receptor has recently been identified, localized in the amygdala, the nucleus of the brain.

The short lifetime of phenylethylamine (minutes) and its destruction under the action of the monoamine oxygenase enzyme are also peculiar. The short lifetime indicates a special biodynamic role of PEA, associated with a very short acting irritation effect. In contrast, other neuroamines (dopamine, serotonin, and norepinephrine) have long lifetimes (hours).

The influence of phenylethylamine on human behavior is usually explained on the basis of M. Liebowitz's hypothesis (also called the "psychochemical hypothesis") about falling in love. Despite the speculative nature of this hypothesis, it allows at least to explain the role of phenylethylamine in the regulation of affects. If we meet someone we like, phenylethylamine starts to be produced in the brain. We, humans, judge the attractiveness of a partner or partner primarily by optical impression, and not by smell or touch, like most mammals. Romantic love can flare up literally at first sight. Synthesis of phenylethylamine in the brain and its distribution throughout the nervous system play a role in the arousal that surrounds us when looking at a loved one, and the desire for it when he is not with us.

Phenylethylamine is found in chocolate, sweets (containing aspartame), diet drinks. And yet, all these sources do not give the result that phenylethylamine secreted by the brain (that is, endogenous) gives. main reason- the rapid destruction of phenylethylamine under the action of the enzyme monoamine oxidase-B (MAO-B) - its main amount is split into initial stage consumption. Love potions exist in the tale of Tristan and Isolde or in Shakespeare's A Midsummer Night's Dream, but in reality our chemical system jealously guards its exclusive right to control our emotions.

7. Trust: Oxytocin

Oxytocin is another hormone and neurotransmitter of the pituitary gland. The physiological effect of oxytocin hormone is to increase the frequency of contractions of the uterus and alveoli of the mammary glands in women. In medicine, Oxytocin is used to induce labor.

Oxytocin is also involved in the sexual arousal response. It is oxytocin that is involved in the erection of the nipples (both in men and women). Thanks to oxytocin, a woman during lactation increases the production of breast milk, in close contact with a newborn baby or if the nipples are irritated.

Some researchers believe that oxytocin is involved in the mechanism of male erection - at least, a positive effect was given by injecting it into certain parts of the brain. However, we can safely say that the role of oxytocin in the mechanism of erection is not decisive.

Relatively recently (2005) was opened psycho-physiological role of oxytocin- neuromodulator. During several experiments, it turned out that oxytocin increases the degree of trust in a particular person.

The experiment involved 178 students of Zurich universities (only men). They were offered to become partners in a game where some acted as investors and others as brokers. At the beginning of the experiment, each participant received a personal financial fund. The investor could keep all this conditional money for himself, or transfer it (all or part of it) to his broker. According to the terms of the game, the broker earned 200% of the profit on each such operation, that is, the "investor's" contribution reached him in a triple amount. In this case, the broker could either keep all this money or return any part of it to the investor. This ended the game, and the partners started counting wins and losses. To create real excitement and selfish interest, the experimenters at the end of the experiment gave out for each " monetary unit"40 very real Swiss centimes.

A key aspect of the experiment was that some investors were given an oxytocin spray to inhale, while others were given a neutral spray. It turned out that investors who received oxytocin had much more confidence in their brokers. 45% of them chose to invest all 12 units of their capital in the business. 21% did not make any investments or showed a minimum of trust. But among the "placebos" everything was exactly the opposite: the maximum trust was 21%, the minimum was 45%.

However, it does not follow from these results that oxytocin actually increases the degree of trust in a business partner. To rule out the interpretation of the experience, supposedly "under the influence of oxytocin, people cease to be afraid to take risks," an additional experiment was set up, with the same conditions. However, the size of the payment received by the investor was no longer determined by the broker, but by a random number generator. In this situation, both groups of "investors" acted in the same way, so that oxytocin had no effect on them. This control experiment showed that oxytocin increases the degree of trust in a particular person, but does not encourage playing at random.

At the moment, it is believed that the level of oxytocin increases with close contact with a person, especially when touched and stroked. Even more oxytocin is released during sexual intercourse, and directly at the moment of orgasm - in both men and women.

Oxytocin is involved in the formation of bonds between people, including bonds between mother and child. Oxytocin lowers the level of anxiety and stress of a person in contact with other people. Oxytocin stimulates the release of endorphins, which cause a feeling of "happiness". A cat that purrs in response to your strokes is a typical example of the action of oxytocin.

An interesting experiment was carried out in 2005. The studies concerned orphans who spent the first months or years of life in an orphanage, and then were adopted by prosperous families. The children played a computer game while sitting on their mother's lap (whether mother or adoptive), after which the level of oxytocin was measured and compared with the level measured before the start of the experiment. On another occasion, the same children were playing the same game on the lap of a strange woman.

It turned out that in domestic children, after communicating with their mother, the level of oxytocin increases markedly, while joint game with an unfamiliar woman did not cause such an effect. In former orphans, oxytocin did not increase either from contact with a foster mother or from communication with a stranger. These sad results show that the ability to enjoy communication with a loved one, apparently, is formed in the first months of life.

8 Attachment: Vasopressin

Vasopressin is a pituitary hormone similar in molecular structure to oxytocin.. Main physiological function vasopressin - an increase in the reabsorption of water by the kidneys, thereby increasing the concentration of urine and reducing its volume.

In 1999, another property of vasopressin was unexpectedly discovered using the example of voles. The fact is that there are two types of mice: steppe vole and mountain vole. At the same time, steppe voles belong to 3% of mammals that realize monogamous relationships. When prairie voles mate, two hormones are released: oxytocin and vasopressin. If the release of these hormones is blocked, sexual relations between prairie voles become as fleeting as those of their "lecherous" mountain relatives. Blocking vasopressin brings the greatest effect.

In this case, the distinguishing feature is the smell.. Rats and mice recognize each other by smell. Scientists claim that prairie voles become attached to each other through the action of the mechanism of sexual imprinting, mediated by smell. Moreover, scientists suggest that in other monogamous animals, including humans, the evolution of the reward mechanism involved in the formation of this attachment proceeded in a similar way, including with the aim of regulating monogamy.

Among the great apes studied, vasopressin levels in the reward centers of the brain were higher in monogamous monkeys than in non-monogamous rhesus monkeys. Animals that establish strong social relationships are thought to do so by virtue of the presence and positioning of their vasopressin and oxytocin receptors. The more receptors there are in areas associated with reward, the more enjoyable social interaction is.

An alternative hypothesis is that vole monogamy is caused by changes in the structure and number of dopamine receptors.

9 Attraction: Pheromones (androsterone and copulins)

In this chapter, for the first time, we will talk about two substances that are very far from neuroscience - but still closely related to the chemistry of human relationships. These are pheromones - products of external secretion, secreted by some animal species and providing chemical communication between individuals of the same species. In the book "Evolutionary Psychology" D. and L. Palmer deals with human pheromones: androsterone and copulins.

Androsterone (or androstenone) - It is a male sex hormone derived from the hormone testosterone. But what is important for us now is not its hormonal action, but the fact that it is contained in the urine and sweat of males of many mammalian species. For example, if you present androsterone to a female pig during ovulation, then she immediately arches her back and assumes a mating position with her legs spread apart. Such a rigid pattern in the reaction is observed in pigs only during ovulation. The rest of the time she is indifferent to this smell.

It's funny that female pigs are looking for delicacy truffle mushrooms precisely because of the substance contained in their smell, similar to androsterone.

Studies in 1986, 1997 showed that men invariably perceive adrosterone as an unpleasant and repulsive odor. Apparently, this smell signals to them about the presence of an opponent nearby. Women who inhaled the substance through their nose expressed similar attitudes, with one important exception: in the middle of the cycle, they rated this smell positively.

A 1998 experiment (double-blind placebo controlled) showed that synthetic androsterone had a positive effect on men's social-sexual behavior: those who used the pheromone had a significant increase in the number of sexual intercourses, and they slept with their romantic partners more often. They also petted more, kissed more, had a greater sense of closeness, and went on dates more often. However, their frequency of masturbation did not change significantly. Thus, it can be assumed that synthetic pheromones enhance the exclusively social aspect sexual behavior That is, attracting the opposite sex.

Copulin female pheromones- are a mixture of vaginal acids. Studies have shown that men under the influence of copulins release testosterone. Copulins perform a role symmetrical to androsterone - they attract a male to a female ready for mating. It is characteristic that the peak of copulin secretion in the female body falls precisely on the period of ovulation.

10. Libido: androgens (testosterone)

Androgens are the common name for male sex hormones.. Despite the fact that the hormones are "male" - they are produced by the sex glands and the adrenal cortex in both men and women. The most important representative of androgens is testosterone.

Androgens are responsible for the excitability of the psychosexual centers of the nervous system. They are playing a key role in the formation of libido(sex drive) - both in men and women. Androgens are hypothesized to increase desire by increasing the sensitivity of certain centers in the limbic system and hypothalamus, as well as by increasing general activity organism due to the stimulating effect of androgens on metabolism. This is confirmed by the fact that testosterone preparations are very effective. medicines to increase libido.

There is evidence that testosterone increases the aggressiveness and sensitivity of erogenous zones. There is also a clear relationship between testosterone levels and the frequency and severity of nocturnal erections. Androgens are believed to increase penile erection in men and clitoral erection in women, and also affect the intensity of orgasmic experiences.

In addition, androgens are responsible for the development of male secondary sexual characteristics: coarsening of the voice, male-type facial hair growth, baldness, male-type fat deposition on the abdomen, increased muscle mass and strength. Therefore, women of the Caucasian peoples, who are distinguished by male facial hair, have an increased libido compared to Caucasians. However, an excessive concentration of androgens in the female body is fraught with pregnancy complications.

11 Femininity: Estrogens (estradiol)

Estrogens are the common name for female sex hormones. produced mainly by the gonads in women. Small amounts of estrogens are also produced by the testes in men and by the adrenal cortex in both sexes. The most characteristic estrogen is estradiol.

Estrogens have a strong feminizing effect on the body: they stimulate an increase in the mammary glands, the formation of a characteristic female form of the pelvis, the deposition of fat according to the female type - on the hips). The secretion of female pheromones directly depends on the level of estrogen.

It's funny that blonde hair is more high rate concentration of estrogen in the blood. A high level of estrogen - a large number of pheromones. Apparently, that's why many men like blondes. After a blonde has her first child, her hair darkens as estrogen levels in her blood fall.

Both estrogens and androgens inhibit the development of cardiovascular diseases of osteoroposis. Only estrogens cope better with cardiovascular diseases, and androgens strengthen bones. As a result, the risk of developing cardiovascular disease in men it is higher, but the bones (especially in old age) are stronger.

Estrogens have a calming and memory-enhancing effect. In 1986-1990, it was found that an increase in estrogen levels helps to block the reuptake of serotonin - and thereby improves mood and general well-being. It is believed that it is the extremely low level of estradiol that is the cause of depression in menopause. Some researchers believe that estrogens along with testosterone increase the level of sexual desire in women.

12. Preparation for conception: progestins (progesterone)

Progestins, and in particular progesterone, are exclusively female sex hormones. Their main function is to ensure the possibility of onset, and then to maintain pregnancy.

If the peak of estrogen occurs at ovulation (this increases sexual desire, the level of pheromones and increases the likelihood of sexual intercourse necessary for conception), then the highest level of progesterone falls on the second stage of the cycle - the body is preparing for a possible pregnancy.

At the moment, there are several theories about the causes of premenstrual syndrome.

Usually, PMS symptoms are associated with sharp decrease the amount of progesterone against the background of a significantly increased concentration of estrogens. Progesterone has an analgesic effect, and an excess of estrogen leads to fluid retention and sodium salts in the intercellular space. It is with excessive hydration of the body and its salt intoxication that the phenomenon of PMS is associated. The nature of the symptoms is determined by the interest of the tissues where edema develops (brain - headache, intestines - bloating, nausea, etc.).

Incidentally, it has been proven that progesterone levels rise in a woman's body at the mere sight of a child but. The infant circuitry that triggers female parental behavior is thus hormonally based. plump body, short legs and arms, large head and big eyes stimulates a powerful release of progesterone in women. Nothing of the kind occurs in contact with babies in men.

The predisposition to a hormonal response to the infantile scheme in women is so strong that this mechanism is triggered even when a woman sees a kitten, puppy, or just a toy teddy bear.

It is the peculiarities of female perception associated with innate maternal instincts that explain the fact that many girls and young women are delighted with soft plush toys with the proportions of an infant body, while long and skinny toys do not cause them any positive reaction.

Men do not produce progesterone me, and they simply do not understand the explosions of tenderness that a grown woman exudes at the sight of a small plush animal.

13. Maternal Instinct: Prolactin

Prolactin is one of the pituitary hormones. The main function of prolactin in the female body is to ensure breastfeeding. Prolactin ensures the development of the mammary glands and the production of milk. Prolactin secretion increases significantly during pregnancy and especially during lactation.. In significantly smaller quantities, prolactin is also produced in men.

One of the side effects of prolactin is that it inhibits the mechanism of sexual arousal., both in men and women. And regardless of the content of testosterone in the blood. That is why during lactation, sexual desire in women is often absent.

It is the release of prolactin during orgasm that is to blame for the sexual cooling that follows immediately after orgasm. Under normal conditions, 60 participants in the experiment, aged 22 to 31, on average needed a break of 19 minutes after orgasm. However, after taking the drug that suppresses prolactin, they received several orgasms in a relatively short time.

It is well known that prolactin stimulates the development of maternal attachment.. Lab monkeys with reduced prolactin levels are more secluded and spend less time in body contact.

It is believed that the secretion of prolactin also increases with stress, depression, pain. Perhaps this mechanism is evolutionary in nature, which reduces the likelihood of conception at the wrong time.

However, despite the increased production of prolactin, in a stressful situation, the females of most mammals have difficulty with breastfeeding. The fact is that when the cub takes the nipple into his mouth, this mechanical stimulation induces the hypothalamus to trigger the release of another pituitary hormone - oxytocin. Its level in the blood rises, the pressure in the mammary gland rises sharply, and milk begins to flow into the baby's mouth. This happens very quickly: it is enough for the cub to suck on the mother for a few seconds for a copious separation of milk to begin.

Adrenaline released during stress suppresses oxytocin, and stops the flow of milk from the breast in difficult moments. Perhaps this mechanism is evolutionary in nature: when a primitive mother and her child ran away from a wild beast, stopping the flow of milk was to her advantage while she fled. As soon as she reached a safe hiding place and calmed down, the flow of milk resumed, and she put the baby to her breast.

14. Intoxication: ethanol

Unfortunately, you can neither eat nor even inject yourself intravenously - neither serotonin nor dopamine. They must be produced inside the brain. Being introduced from the outside, these substances are not able to overcome the blood-brain barrier that protects the brain from foreign substances.

But the blood-brain barrier is remarkably overcome by nicotine, opiates, and of course alcohol..

Unlike drugs that have a high affinity for the corresponding receptors (for example, drugs of the opium group), ethanol molecules do not act directly on receptors, but impregnate the lipid layer of the neuron membrane, dilute it, causing the process of fluidization. In a loosened membrane, the receptor loses its support, its conformation changes and a feeling of intoxication arises.

Ethanol intake increases the turnover of serotonin. An increase in the permeability of vesicle membranes contributes to the leakage of the mediator into the presynaptic cleft and the realization of its effect. Having acted, it is intensively cleaved to 5-hydroxyindoleacetic acid. A decrease in the concentration of serotonin in the hypothalamus serves as a factor that increases the desire to drink.

A single intake of alcohol leads to the activation of the processes of formation and use of norepinephrine but. Its content is reduced due to increased release of the neurotransmitter from the vesicles and its accelerated decay. Increased circulation of norepinephrine in the midbrain and hypothalamus explains the phase of motor, vegetative and emotional arousal associated with alcohol consumption. Depletion of noradrenaline reserves leads to a depressed state, mental and motor retardation.

The well-known alcohol hangover syndrome is caused by intoxication of the body with the product of ethanol oxidation - acetaldehyde, which the liver does not have time to finally break down into harmless acetic acid.

We examined the chemicals involved in mental processes human body. Now, seeing this or that behavioral reaction, you can immediately determine what chemical process is behind it. But do not forget that in addition to chemistry there is also psychology!published

1. What substances are called hormones? What are their main properties?

Hormones are chemical compounds with high biological activity, secreted by endocrine glands.

Properties of hormones:

produced in small quantities
the distant nature of the action (the organs and systems that hormones act on are located far from the place of their formation, therefore hormones are carried throughout the body with the bloodstream);
remain active for a long time;
strict specificity of action;
high biological activity;
regulate metabolic processes, ensure the constancy of the composition of the environment, affect the growth and development of organs, provide the body's response to the external environment.

According to their chemical nature, hormones are divided into three groups: polypeptides and proteins (insulin); amino acids and their derivatives (thyroxine, adrenaline); steroids (sex hormones).

If an increased amount of hormones is formed and released into the blood, this is hyperfunction. If the amount of hormones produced and released into the blood decreases, then this is hypofunction.

2. What glands produce hormones? Name them. What effect do the hormones of these glands have on the body?

The thyroid gland is located on the neck, in front of the larynx, produces hormones rich in iodine - thyroxine, etc. They stimulate the body's metabolism. The level of oxygen consumption by the organs and tissues of the body depends on their amount in the blood, i.e. hormones thyroid gland stimulate oxidative processes in cells. In addition, they regulate water, protein, fat, carbohydrate, mineral metabolism, growth and development of the body. Have an effect on the functions of the central nervous system and higher nervous activity. Lack of the hormone in childhood leads to cretinism (growth, sexual and mental development is delayed, body proportions are disturbed). With hypofunction in an adult, myxedema develops (decreased metabolism, obesity, lowering body temperature, apathy). With hyperfunction in adults, Graves' disease occurs (enlargement of the thyroid gland, development of goiter, bulging eyes, increased metabolism, increased excitability of the nervous system).

Adrenals. Small bodies above the kidneys. They consist of two layers: outer (cortical) and inner (brain). The outer substance produces hormones that regulate metabolism (sodium, potassium, proteins, carbohydrates, fats), and sex hormones (cause the development of secondary sexual characteristics). With insufficient function of the adrenal cortex, a disease develops, which is called bronze disease. The skin acquires a bronze color, there is increased fatigue, loss of appetite, nausea. With hyperfunction of the adrenal glands, an increase in the synthesis of sex hormones is noted. At the same time, secondary sexual characteristics change. For example, women get mustaches, beards, and so on.

The internal substance produces the hormones adrenaline and norepinephrine. Adrenaline speeds up the circulation of blood, increases the heart rate, mobilizes all the forces of the body in stressful situations, increases blood sugar (breaks down glycogen). The amount of adrenaline is under the control of the central nervous system, there is no shortage. In excess, it speeds up the work of the heart, constricts blood vessels. Norepinephrine slows down the heart rate.

Pancreas. It is located in the abdominal cavity of the body, below the stomach. It is a gland of mixed secretion, has excretory ducts and secretes enzymes involved in digestion. Individual cells of the pancreas secrete hormones into the blood. One group of cells produces the hormone glucagon, which promotes the conversion of liver glycogen into glucose, resulting in an increase in blood sugar levels. Other cells produce insulin. This is the only hormone that lowers blood sugar (promotes the synthesis of glycogen in liver cells). In case of pancreatic insufficiency, the development diabetes. This raises the level of sugar in the blood. Carbohydrates are not stored in the body, but are excreted in the urine in the form of glucose.

The sex glands - the testes in men and the ovaries in women - also belong to the glands of mixed secretion. Due to the exocrine function, sperm and eggs are formed. Endocrine function is associated with the production of male and female sex hormones that regulate the development of secondary sexual characteristics. They influence the formation of the body, metabolism and sexual behavior. Androgens are produced in the testicles. They stimulate the development of secondary sexual characteristics characteristic of men (growth of a beard, mustache, muscle development, etc.), increase basal metabolism, and are necessary for the maturation of spermatozoa.

In the ovaries, female sex hormones are formed - estrogens, under the influence of which the formation of secondary sexual characteristics characteristic of women occurs (body shape, development of the mammary glands, etc.) material from the site

Pituitary. It is located below the bridge of the brain and consists of three lobes: anterior, intermediate and posterior. The anterior lobe secretes growth hormone, which affects the growth of bones in length, accelerates metabolic processes, leads to increased growth, and an increase in body weight. The lack of a hormone is dwarfism, while the proportions of the body and mental development are not violated. Hyperfunction in childhood leads to gigantism (children have long limbs, they are not physically strong enough), in adults acromegaly occurs (the size of the hand, foot, front of the skull, nose, lips, chin increase). Hypofunction in adults leads to a change in metabolism: either to obesity or to a sharp weight loss.

The intermediate lobe of the pituitary gland secretes a hormone that affects skin pigmentation.

The posterior lobe is formed by nervous tissue. It does not synthesize hormones. Biologically active substances produced by the nuclei of the hypothalamus are transported to the posterior lobe of the pituitary gland. One of them selectively affects the contraction of the smooth muscles of the uterus and the secretion of the mammary glands. Other boosts blood pressure and delays the excretion of urine. With a decrease in the amount of this substance, urination increases to 10-20 liters. per day. This disease is called diabetes insipidus.

Didn't find what you were looking for? Use the search

On this page, material on the topics:

what are hormones and what are their properties
hormones briefly about them
hormones summary
name the main properties of hormones
name the temporary glands, what hormones they produce and what is their significance

essay on hormones. I mean who opened and others in short and got the best answer

Answer from Southern Beauty[guru]
In what, in what?

Answer from Maria[active]
History
Discovered in 1902 by Starling and Bayliss.
Purpose
They are used in the body to maintain its homeostasis, as well as to regulate many functions (growth, development, metabolism, response to changes in environmental conditions).
Receptors
All hormones realize their effect on the body or on individual organs and systems with the help of special receptors for these hormones. Hormone receptors are divided into 3 main classes:
receptors associated with ion channels in the cell (ionotropic receptors)
receptors that are enzymes or associated with signal transducer proteins with an enzymatic function (metabotropic receptors, such as GPCRs)
receptors for retinoic acid, steroid and thyroid hormones that bind to DNA and regulate the functioning of genes.
All receptors are characterized by the phenomenon of self-regulation of sensitivity through a feedback mechanism - with a low level of a certain hormone, the number of receptors in tissues and their sensitivity to this hormone automatically increase compensatory - a process called sensitization (and also up-regulation, or sensitization ( sensitization)) receptors. Conversely, when the level of a certain hormone is high, there is an automatic compensatory decrease in the number of receptors in tissues and their sensitivity to this hormone - a process called desensitization (and also down-regulation, or desensitization) of receptors.
An increase or decrease in hormone production, as well as a decrease or increase in the sensitivity of hormonal receptors and a violation of hormonal transport leads to endocrine diseases.
Mechanisms of action
When a hormone in the blood reaches the target cell, it interacts with specific receptors; receptors "read the message" of the body, and certain changes begin to occur in the cell. Each specific hormone corresponds exclusively to “its own” receptors located in specific organs and tissues - only when the hormone interacts with them, a hormone-receptor complex is formed.
The mechanisms of action of hormones can be different. One group is made up of hormones that bind to receptors located inside cells - usually in the cytoplasm. These include hormones with lipophilic properties - for example, steroid hormones (sex, gluco- and mineralocorticoids), as well as thyroid hormones. Being fat-soluble, these hormones easily penetrate the cell membrane and begin to interact with receptors in the cytoplasm or nucleus. They are slightly soluble in water, and when transported through the blood, they bind to carrier proteins.
It is believed that in this group of hormones, the hormone-receptor complex plays the role of a kind of intracellular relay - having formed in the cell, it begins to interact with chromatin, which is located in the cell nuclei and consists of DNA and protein, and thereby speeds up or slows down the work of certain genes. . By selectively influencing a specific gene, the hormone changes the concentration of the corresponding RNA and protein, and at the same time corrects metabolic processes.
The biological result of the action of each hormone is very specific. Although hormones usually change less than 1% of proteins and RNA in the target cell, this is quite enough to obtain the corresponding physiological effect.
Most other hormones are characterized by three features:
they dissolve in water;
do not bind to carrier proteins;
they begin the hormonal process as soon as they are connected to the receptor, which can be located in the cell nucleus, its cytoplasm, or located on the surface of the plasma membrane.
The mechanism of action of the hormone-receptor complex of such hormones necessarily involves mediators that induce a cell response. The most important of these mediators are cAMP (cyclic adenosine monophosphate), inositol triphosphate, and calcium ions.

Send your good work in the knowledge base is simple. Use the form below

Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.

"Chemistry of hormones"

1. Gonadotropins

Gonadotropins, FSH (follicle-stimulating hormone, follitropin) and LH (luteinizing hormone, lutropin) are glycoproteids secreted by cyanophilic cells of the adenohypophysis (anterior pituitary gland), under the action of the hypothalamic releasing factor. The target organs are the gonads.

The molecular weight of FSH is 33,000 daltons and LH is 28,000 daltons. Both hormones have a dimeric structure, i.e. consist of a hormonally non-specific alpha chain (this chain is interchangeable with FSH and LH) and a beta chain that determines hormonal specificity. The chains are linked by a non-covalent bond. The high content of saccharides up to 16% also plays an important role in determining the biological activity. When the saccharide shell is removed from the surface of the hormone, the latter partially loses its biological activity, while the immunological activity remains unchanged (determination by immunological methods is possible). The structure of the alpha chain in these hormones is very similar to that of hCG and TSH. An isolated alpha or beta chain has virtually no biological activity.

The molecular structure of both hormones is heterogeneous, which is determined by age and sex and possibly induced by sex steroids. To date, it has not been established whether this heterogeneity has any clinical significance.

FSH and LH carry out their hormonal activity through receptors on the surface of the gonadal target cell; in this process the corresponding hormone acts as a first-order messenger. Then, in the process of a cascade of successive reactions, the hormonal impulse propagates in the target cell with the help of cyclic AMP, a second-order messenger (see Fig. 1). In interaction with estradiol, FSH induces its receptors; LH receptors are also induced by FSH.

In women, LH and FSH have a synergistic effect on the biosynthesis of ovarian steroid hormones. The targets of LH are the cells of the ovarian membrane and the corpus luteum. In addition, LH induces ovulation and luteinizes granulosa cells. FSH controls the growth of follicles until they are mature and ready for ovulation, and from early stages biosynthesis of steroids, the synergistic interaction of FSH and LH also stimulates the biosynthesis of estradiol by granulosa cells.

In men, LH stimulates the biosynthesis of testosterone in the Leydig cells of the testicles. FSH controls the growth and function of the seminiferous tubules, especially spermatogenesis in Sertoli cells.

Gonadotropes FSH=follicle-stimulating hormone, follitropin Site of synthesis: anterior pituitary gland Glycoproteins: saccharide content approx. 16% Molecular weight: 33,000 daltons Dimeric structure: alpha and beta chains; Beta chain determines hormonal specificity Target organs: ovaries, testes

LH=luteinizing hormone, luteinizing site Synthesis: anterior pituitary gland Glycoproteins: saccharide content approx. 16% Molecular weight: 28,000 Dimeric structure: alpha and beta chains; Beta chain determines hormonal specificity Target organs: ovaries, testes

2. Prolactin

Unlike gonadotropins, prolactin consists of a single peptide chain of 198 amino acid residues. Among other things, the spatial structure of the hormone is stabilized by three disulfide bridges. Prolactin does not contain saccharide residues, that is, it is not a glycoprotein. The molecular weight of the hormone is 22,000 doltons. There are certain structural analogies with growth hormone (somatotropin, growth hormone, STH), as well as with human placental lactogen (HPL).

Prolactin circulating in the blood is characterized by molecular polymorphism, i.e. it can be "small", "large" and "very large", while the immunogenicity of these forms is the same. It is assumed that "small" prolactin is a monomeric form, and "large" and "very large", respectively, di- and tetrameric. "Small" prolactin is approximately 80% of the total amount of the hormone, immunologically determined in the blood, "large" - 5-20%, and "very large" - 0.5-5%. Moreover, the serum contains degraded prolactin, which is immunologically active and has a molecular weight of 8,000 to 16,000 daltons. Animal experiments have shown a strong mitogenic effect of this prolactin on breast tissue.

Like gonadotropins, prolactin exerts its physiological effect on target cells through receptors located on the membrane. Together with estradiol, prolactin in women affects the growth and functioning of the mammary glands and causes lactation. According to some researchers, prolactin plays a role in the formation and function of the corpus luteum.

In men, the specific function of prolactin has not been established.

Prolactin is synthesized in specialized lactogenic cells of the anterior pituitary gland; its synthesis and liberation are under<лимуляционно-ингибиторнь1м влиянием гипоталамуса. Кроме гипофиза, пролактин продуцируется децидуалъной оболочкой (наличие пролактина в амниотической жидкости) и эндометрием.

Prolactin

Site of synthesis: anterior pituitary gland (also decidua and endometrium) Single peptide chain (198 amino acids) stabilized by three disulfide bridges Not a glycoprotein! Target organ: mammary glands

3. Luliberin

Luliberin (luteinizing hormone releasing factor), also called gonadoliberin (gonadotropin releasing factor) is a decapeptide of known structure. Luliberin is synthesized in nerve cells (neurons) of certain areas of the ventral and mediobasal hypothalamus (Nucleus arcuatus, ventromedialis, periventricularis anterior, area preoptica suprachismatica), which are identified immunohistochemically. Through the axons of nerve cells, the hormone is transported to the medial eminence (Eminentiamediana), where it is released into the blood by a special portal system that covers the hypothalamus, the pituitary stalk and the adenohypophysis. In the anterior pituitary gland, luliberin stimulates the synthesis and release of LH and FSH through specific binding to receptors on the cell membrane of the adenohypophysis. Variations in the level of gonadotropins in women, as well as differences in the ratio of FSH and LH depending on the age and phases of the menstrual cycle, are probably due to changes in the functional state of the gonadotropic cells of the anterior pituitary gland (variations in the number of receptors for luliberin, which determines the sensitivity of gonadotropes to it). Inhibin also has a modeling effect on this mechanism. Luliberin is catabolized and inactivated by adenohypophysis endopeptidases.

Luliberin

Luliberin = (releasing factor of luteinizing hormone) Synonym: gonadoliberin (gonadotropin-releasing factor) Place of synthesis: hypothalamus; decapeptide Orgai target: anterior pituitary gland

4. Inhibin

Inhibin is a peptide with a molecular weight of 23,000 daltons. In women, the hormone is found in the follicular fluid, while in men it is synthesized in the seminiferous tubules of the testicles. Inhibin selectively inhibits the release of FSH from the anterior pituitary gland.

5. Sex steroids

All steroid hormones are based on the cyclopentane-perhydrophenanthrene structure, also called the sterane ring system, which consists of four hydrogen-saturated condensed rings, three of which are six-membered and one five-membered (see Fig. 2). By replacing hydrogen atoms with a methyl group or oxygen-containing oxo- or hydroxyl groups, a significant variety of physiological effects of hormones is achieved.

In the female body, the place of synthesis of the most important sex steroids (i.e. estrogens, gestagens and androgens) are the ovaries and adrenal cortex, and during pregnancy - the placenta. Principal sex steroids for the male body are androgens, which are synthesized in the testicles and, in small quantities, in the adrenal cortex. In addition to what has been said, it should be noted that the supplier of cholesterol, the derivatives of which are all sex steroids and hormones of the adrenal cortex, is the liver.

Steroids are lipophilic, which means they have a low ability to dissolve in water. Therefore, in the blood, 95% of steroid hormones are in a bound state with specific transport proteins. The equilibrium between bound and free steroids obeys the law of mass action. With the help of transport proteins, hormones are transported to their target organs. Only free, non-protein bound steroids are biologically active. Sexsteroid binding globulin (SHBG) specifically binds estradiol and androgens with low capacity and high affinity, while corticosteroid-binding globulin (CBG) binds progesterone and glucocorticoids. In addition to their transport function, specific serum hormone-binding proteins protect steroids from metabolic inactivation along the way from the secreting gland to the target organ. SSSG and KSG are acidic glycoproteins with a molecular weight of 45,000 (SSG) and 65,000 (KSG). The synthesis of steroid hormones occurs completely in the human body (see Fig. 3). The initial substance - CoA, activates acetic acid - a carbon compound, from which cholesterol is formed as a result of a series of transformations, further condensation and cyclization. Cholesterol consists of 27 carbon atoms and, among other components, is the main component of the initial stage of the synthesis of steroid hormones.

Pregnenolone is formed by enzymatically mediated shortening of the side chain attached to the steroid structure at position 17c by 6 carbons. Pregnenolone is a C21 steroid, from which, subsequently, progesterone is formed by the oxidation of the hydroxyl group in position 3b to an oxo group with the simultaneous movement of the double bond from D 5 to D 4 . Progesterone is the main representative of the gestagens. At the same time, progesterone is the precursor of all gluco- and mineralcorgycoids (see Fig. 2), as well as androgens, which are derived from progesterone as a result of enzymatic cleavage of the side chain at position 17c. In this process, 17-hydroxyprogesterone acts as an intermediate. This means that androgens are C19 steroids, of which testosterone is the main representative.

At the end of a complex synthetic chain, which consists of many intermediate reactions, estrogens are synthesized, the most active representative of which is estradiol. Estrogens are synthesized from androgens by removing the angular C19 methyl group located between rings A and B with simultaneous aromatization ("phenolization") of the A ring. The phenolic ring A is the most characteristic feature of all estrogens.

All steroid hormones are degraded in the liver by reduction, addition of hydroxyl groups, followed by conjugation with glucuronic acid or sulfation. As a result, water-soluble compounds are formed that can be excreted in the urine.

Unlike gonadotropins, steroid hormones exhibit their biological effect by penetrating into the cell along a concentration gradient and binding to soluble receptor molecules present in the cytosol, and not by interacting with membrane receptors (see Fig. 4). Each group of steroid hormones has its own specific receptors. The binding to the corresponding receptor is reversible and has a high affinity.

The resulting cytoplasmic steroid-receptor complex is gradually activated or transformed and moves into the cell nucleus - the location of the genetic apparatus. Here, the hormone-receptor complex interacts with a specific molecular region on the chromatin, the so-called nuclear interaction zone, which corresponds to a molecular region on the steroid-receptor complex. As a consequence of the binding of the steroid hormone receptor complex to the nuclear acceptor, the DNA double helix is cleaved, making the genetic information available.

This segment of DNA is transcribed into mRNA. Further, having separated, the mRNA enters the cytoplasmic space. At the final stage, in the process of interaction of mRNA (as a matrix) with the ribosomal protein-synthesizing apparatus, protein neosynthesis occurs.

5.1 Estrogens

The main representative of estrogens is estradiol (see Fig. 5), which has the highest biological activity. Estrone is formed from estradiol by enzymatically mediated dehydrogeneration at C17 and does not have a pronounced biological activity (due to its low ability to bind to the receptor and insufficient accumulation in the cell nucleus). During pregnancy, estrone can be detected in serum in increasing concentrations. In this case, the hormone is synthesized from dehydroepiandrosterone sulfate (DHEA - S), which is formed in the adrenal cortex of the fetus. Thus, estrone is one of the indicators characterizing the state of the fetus.

Another interesting group of estrogens are the catechol estrogens, ie. steroids derived from estradiol and estrone and having an additional group in the second position of the ring A. This makes them similar to catecholamines: adrenaline and norepinephrine. Catecholestrogens, among other places, are synthesized in the hypothalamus, where they, according to many researchers, act as neurotransmitters, like catecholamines.

In the female body, estradiol is synthesized in the ovaries, in the membrane and granulosa cells of the follicles. During the luteal phase of the menstrual cycle, estradiol is synthesized exclusively by the follicle sheath cells, while the granulosa cells become luteinized and switch to progesterone synthesis. In the event of pregnancy, massive production of estrogens is carried out by the placenta. To other sites of estrogen synthesis, primarily estrone in postmenopausal women,

includes the adrenal cortex and peripheral adipose tissue due to their ability to aromatize androgens.

Clinically reliable evidence of the presence of estrogen secretion in the male body has not been found.

The target organs of estrogen are the uterus, vagina, vulva, fallopian tubes, and mammary glands. Hormones of this group are responsible for the development of secondary sexual characteristics and determine the characteristic physical and mental characteristics of women. Estrogens also cause the closure of epiphyseal growth points and thus take part in the regulation of linear growth. In addition, estrogens have an inducing effect on a number of plasma proteins synthesized in the liver (for example, SSH, KSH, TSH-thyroxine-binding globulin, lipoproteins, blood coagulation factors). In target cells, estradiol induces both its own receptors and progesterone receptors.

5.2 Gestagens

The main representative of this group of hormones is progesterone (see Fig. 2). In women, progesterone is secreted by the corpus luteum and, during pregnancy, by the placenta.

Clinically reliable evidence of the presence of progesterone synthesis in men does not exist.

In order for progesterone to manifest its physiological effect in the female body, preliminary exposure to estrogens is required. As with estradiol, progesterone activity in target cells is mediated by specific receptors. The activation of this group of receptors occurs similarly to the mechanism of activation of estrogen receptors.

The main target organ for progesterone is the uterus. The hormone causes a secretory transformation of the proliferative thickened endometrium, thereby ensuring its readiness for implantation of a fertilized egg. Moreover, progesterone has an important control function in the gonadotropin-gonadal steroid system and causes stimulation of the thermal center. This causes an increase in body temperature of 0.5 degrees in the luteal phase of the menstrual cycle after ovulation.

Progesterone blocks the synthesis of its own receptors, as well as the blocker of estradiol. In the endometrial cell, progesterone induces 17|3-hydroxysteroid dehydrogenase, which is a key enzyme in the metabolism of estradiol and converts estradiol to a practically inactive estrone. Thus, through its receptor mechanism, progesterone prevents the excessive formation of endogenous estradiol in the target cell. This effect of progesterone, in combination with its negative effect on estradiol receptors, is carried out through a receptor mechanism, can be defined as the antiestrogenic effect of progesterone.

5.3 Androgens in women

The main representatives of androgens in the female body are testosterone, androstenediol and dihydroepiandrosterone sulfate (DHEA-S) (see Fig. 6).

In the ovaries, androgens are secreted in the cells of the inner part of the follicle shell, its outer wall; androsterone and testosterone are synthesized from cholesterol under the influence of LH.

Androgens stimulate the growth of pubic and axillary hair, increase libido and affect clitoris size and

large labia. Androgens modulate the production of gonadotropins in the anterior pituitary gland. Hyperandrogenemia in women leads to virilization and fertility disorders. This determines the importance of determining androgens in the diagnosis of female infertility.

Like all steroid hormones, androgen activity is mediated by intracellular receptors. However, it is not testosterone that comes into contact with the receptor, but 5a-dihydrotestosterone (DHT), which is formed in the target cell by enzymatic reduction of the D 4 double bond (due to the activity of 5a-reductase).

5.4 Androgens in men

In the body of men, the main representatives of androgens are testosterone and dihydrotestosterone (DHT). In target organs (prostate, seminal vesicles and skin), testosterone acts as a prehormone; this means that testosterone, upon reaching the target organ, is converted into dihydrotestosterone by 5a-reductase, and only then does dihydrotestosterone exert its biological effect through the receptor mechanism described above. In other target organs, such as muscles and kidneys, the effect of androgens is mediated directly, i.e. without enzymatic conversion. Currently, scientific circles are considering the presence of a third cause-and-effect mechanism at the level of the hypothalamus and in other areas of the brain sensitive to endocrine influences; testosterone as such does not have its own hormonal activity, however, having undergone aromatization, it is transformed into estradiol, acquiring in this case biological activity, interacting with receptors.

Compared to testosterone, the biological activity of other androgens such as androstenedione, dihydroepiandrosterone, dehydroepiandrosterone sulfate, androsterone, epiandrosterone and etiocholanolone is 5-20 times lower. Table 2 shows the normal concentrations of the most important androgens in the body of a man.

Table 2. Normal concentrations of the clinically most significant androgens in men

Dehydroendrostphon sulfate is produced in the adrenal cortex. This androgen is present in the largest amount, but, like testosterone, it essentially has no androgenic activity. The most important source of testosterone is the Leydig cells of the testicles, which was found in the examination of men subjected to castration. Only small amounts of testosterone are synthesized in the periphery by transformation of precursors. Testosterone supports spermatogenesis, stimulates the growth and functioning of the accessory sex glands, as well as the development of the penis and scrotum. The hormone has an anabolic effect, mainly on bones and muscles. During puberty, the presence of testosterone causes the larynx to grow linearly, leading to a deepening of the voice. Under the influence of testosterone, a male type of hair growth is formed (“triangle” in the upper part of the pubis, beard, chest hair, hair loss on the forehead and crown of the head). Due to a direct effect on the bone marrow, as well as by activating the synthesis of erythropoietin in the kidneys, testosterone stimulates erythropoiesis. The hormone is also necessary to maintain libido and potency.

Hormones chemistry. The Chemistry of Love: A Scientific View

Send your good work in the knowledge base is simple. Use the form below

Similar Documents