Hormones of the posterior lobe of the pituitary gland. What is vasopressin responsible for? Man turns pale oxytocin and vasopressin physiology

- Axons extend from the neurosecretory nuclei of the hypothalamus (supraoptic and paraventricular) to the pituitary gland

- These axons carry hormones packed into granules into the posterior lobe of the pituitary gland.

- There is no hormone synthesis in the posterior lobe of the pituitary gland (neurohypophysis).

- The anterior part of the pituitary gland (adenohypophysis) secretes a whole set of peptide hormones. The adenohypophysis is under the control of special chemical factors that are secreted by the neurons of the hypothalamus and released from the axon endings of these cells in the median eminence at the base of the pituitary stalk, from where the blood flow reaches the adenohypophysis cells. Four of these factors are called liberins, and tristatins

- Liberins stimulate the secretion of the corresponding hormones by the cells of the adenohypophysis

- Statins inhibit the secretion of the corresponding hormones

- Liberins and statins are short peptides consisting of a small number

amino acid residues. The membrane type of reception is characteristic.

Corticoliberin is produced in the hypothalamus, stimulates the release of ACTH into the blood

Thyroid-releasing hormone of the hypothalamus (short peptide) consists of 3 amino acid residues, regulates the synthesis and release of thyroid-stimulating hormone, can directly influence brain cells, activating emotional behavior and maintaining wakefulness, increasing breathing, suppressing appetite, mitigating the course of depression

Luliberin - hypothalamic liberin, which controls the regulation of gonadotropins (follicle-stimulating and luteinizing hormones) consists of 10 amino acid residues; It is also able to act on brain cells, activating sexual behavior, increasing emotionality and improving learning and memory.

A decrease in luliberin is found in anorexia nervosa

Somatoliberin stimulates the formation and release of somatotropin

Somatostatin inhibits these processes

It is also worth noting that in the islets of Largehans (pancreas), in delta (15%), somatostatin is produced.

PROLAKTO-STATIN (Prolactin) from dopamine

Melanostatin inhibits the release of melanocyte-stimulating hormone. In addition to the direct effect on the pituitary gland, it activates emotional and motor activity, directly affecting brain functions. Has an antidepressant effect and is used for Parkinsonism

- From the nerve endings of the cells of the hypothalamus, 2 peptide hormones enter the vessels of the posterior lobe of the pituitary gland, each of which consists of 9 amino acid residues: antidiuretic hormone (ADH = vasopressin) and oxytocin

- The target organ for vasopressin is the kidney

- Vasopressin is produced in neurons of the supraoptic nucleus of the hypothalamus, enters the posterior lobe of the pituitary gland along axons, and from there, through the bloodstream, reaches the collecting ducts and excretory ducts of the kidneys.

- Under the influence of vasopressin, the reabsorption of water from urine increases, which prevents large fluid losses

- In increased concentrations, vasopressin acts on the muscles of the artery walls: they contract, the vessels narrow and blood pressure increases.

- Vasopressin - “vasoconstrictor”

- The release of vasopressin into the blood increases with large blood losses, when the pressure drops and needs to be increased

- Vasopressin also affects the brain and is a natural stimulator of learning and memory.

- In small doses, it can accelerate learning, slow down forgetting, and restore memory after severe injuries.

- With a decrease in vasopressin doses (due to traumatic brain injuries, brain tumors and meningitis), diabetes insipidus develops

- Symptoms of the disease:

1) a sharp increase in urine volume (up to 20 liters per day)

In this case, excess sugar in the urine as if diabetes mellitus No. This is due to the fact that without vasopersin it is impossible to ensure the reabsorption of water from urine into the blood

Now they have learned to produce vasopressin synthetically and use it to treat diabetes insipidus

In severe cases, the target organ is not able to respond even to large concentrations of vasopressin, this is due to the fact that vasopressin receptors located in the collecting ducts and excretory ducts lose sensitivity to the hormone.

Oxytocin (OT) in most cases is produced in neurons of the paraventricular nucleus of the hypothalamus, transported along axons to the neurohypophysis and from there enters the blood

Target tissues of OT: smooth muscle of the uterus and muscle cells surrounding the ducts of the mammary glands and testes

Towards the end of pregnancy (after 280 days), the secretion of oxytocin increases, which leads to contraction of the smooth muscles of the uterus, the fetus moves towards the cervix and vagina, which leads to childbirth. After childbirth, oxytocin secretion is inhibited

If the secretion of oxytocin is insufficient, childbirth is impossible: it is necessary to resort to artificial stimulation by injecting the woman in labor with synthetic oxytocin

What hormones are produced in the posterior lobe of the pituitary gland and why are they necessary? It is often believed that the posterior lobe of the pituitary gland secretes the hormones vasopressin and oxytocin, which affect many processes in the body. However, this is not entirely correct.

In fact, the hormones of the posterior lobe of the pituitary gland are formed in the hypothalamus, namely in the supraoptic and supraventricular nuclei, and then through special pathways - axons - they enter the neurohypophysis.

Previously, it was believed that the hormones of the posterior lobe of the pituitary gland were oxytocin, vasopressin, and also antidiuretic hormone, which was considered different from vasopressin. It was later proven that antidiuretic hormone, or adiurectin, and vasopressin are the same substance.

In the posterior part of the pituitary gland, which accumulates hormones, they enter along axonal pathways thanks to a specific transport protein - neurophysin. Next, hormones are deposited in the neurohypophysis and released into the blood as needed.

Hormones of the anterior and posterior pituitary glands can mutually influence each other's functions. Thus, vasopressin enhances the secretion of some pituitary tropic hormones, such as somatotropin, thyrotropin, corticotropin, and also stimulates the formation of cortisol and insulin. It is also important to note the effect on the synthesis of coagulation factors - von Willebrand factor and antihemophilic globulin A, stimulation of glycogenolysis in the liver, as well as the effect on reducing body temperature.

The hormone produced by the posterior lobe of the pituitary gland, oxytocin, is especially important for its effect on the muscles of the uterus, on lactation, as well as in the formation of emotional and mental functions. Being a neurotransmitter, in women it is responsible for the formation of the maternal instinct, and in men it enhances potency. It is believed that in excessive quantities, oxytocin increases irritability, aggression, and anger.

Vasopressin and oxytocin can mutually influence each other's functions and jointly help stimulate brain activity.

Also, the posterior lobe of the pituitary gland secretes hormones whose functions are similar to hypothalamic hormones, but are expressed to a much lesser extent. These include isotocin, valitocin, mesotocin and some others.

The hormones of the middle and posterior lobes of the pituitary gland are of great importance for the normal functioning of the body, no less than the hormones of the adenohypophysis.

Oxytocin

Oxytocin is a pituitary hormone that is produced by the nuclei of the hypothalamus and then accumulates in the posterior lobe of the pituitary gland. This biologically active substance is produced in both female and male bodies.

The functions of oxytocin, in addition to influencing human physiology, also include influencing his psychological state and some mental functions.

It is believed that this hormone is responsible for emotional attachment, strengthening emotional connections between people. It has been proven that the higher the concentration of oxytocin, the stronger the attachment a person develops to his partner, mother, and child. Therefore, it is believed that oxytocin is an attachment hormone. Moreover, oxytocin also helps in social adaptation, and drugs containing oxytocin are used in the treatment of autism.

Also, an increase in oxytocin levels is associated with increased sexual arousal and sexual behavior. For example, if hugs occur, the hormone oxytocin increases the sexual desire of partners, as during kissing, physical intimacy. At the same time, your mood improves and a romantic mood appears. Therefore, there is another assumption: oxytocin is the love hormone.

Oxytocin reduces the effects of stress on the body. When the hormone is produced in sufficient quantities, the body's adaptive capabilities improve, anxiety, fear, and anxiety levels decrease. Emotional memory is also enhanced and more vivid memories are formed. Because of this, it is believed that oxytocin is the hormone of happiness. Oxytocin also helps reduce cravings for smoking, alcohol, and drugs. This property is widely used in the treatment of withdrawal symptoms, in the treatment of drug addiction and alcoholism.

However, the functions of oxytocin are not limited to just influencing mental sphere. The influence of oxytocin on the body, especially on women, is indispensable for the regulation labor activity, secretion of breast milk.

Why is oxytocin (hormone) produced, its functions in the body:

• In women: during childbirth, stimulates the contractile activity of the myometrium; stimulates uterine contraction in the first hours after birth; at breastfeeding stimulates the contraction of myoepithelial cells of the mammary glands, as a result of which milk flows from the alveoli into the excretory ducts, and lactation becomes possible; causes luteolysis of the corpus luteum in the second trimester of pregnancy; stimulates the secretion of prolactin.
• As a gastrointestinal hormone: stimulates the electrical and motor activity of muscle cells of the small intestine.
• It has an antipyretic effect by inhibiting the secretion of endogenous pyrogen in mononuclear cells.
• Participates in the formation of the feeling of thirst and in the regulation of eating behavior.
• Presumably a vasopressin antagonist.
• Reduces salt appetite.
• Stimulates cellular immunity.
• Has an insulin-like effect on adipose tissue.

Most often, oxytocin is in the form medicinal product used in obstetric practice. The hormone oxytocin is also produced in the male body, but sometimes it is administered artificially to men. It is mainly used by athletes for faster muscle recovery after intense training, wound healing, rejuvenation, and mood enhancement. However, an excess amount of oxytocin has an adverse effect on the male body - libido decreases and impotence develops.

How to produce the hormone oxytocin naturally? Since it is a hormone of affection, love, and happiness, its concentration increases with positive emotions, rest, hugs, bodily contact with a pleasant person, communication with loved ones, massage, and touch. Human interactions in society, supported by positive emotions - sports, dancing, walking - have a good effect on the secretion of prolactin. A large peak in the release of the hormone is observed in women immediately after childbirth and when attaching a newborn to the breast - this helps to forget the pangs of labor and form a strong attachment to the child. By the way, one of interesting facts is that oxytocin is produced to a greater extent at night and therefore, most often, it is at night that pregnant women experience contractions - both training and labor.

It is also important to know, when analyzing oxytocin, which hormone regulates its production. The main influence on the secretion of oxytocin is exerted by estrogens. The secretion of oxytocin increases before ovulation, during childbirth during cervical dilatation, during breastfeeding, and during sexual intercourse. An increase in hormone secretion occurs with an increase in osmotic pressure environment, and the decrease in output occurs when severe pain, increased body temperature, when exposed to loud sounds.

Knowing what the hormone oxytocin affects and what it is responsible for normally, you need to know the reasons for its pathological decrease:

• during menopause, especially with a pathological course menopause;
• for pathology thyroid gland;
• with chronic stress;
• viral infections;
• infectious diseases nervous system, in particular, the brain;
• autism;
• Parkinson's disease;
• drug addiction;
• in old age.

The consequences of oxytocin deficiency can be very disastrous: pathological course of labor, hypotonic postpartum hemorrhage, lactation disorders, postpartum depression and psychosis, disruption of the formation of the maternal instinct and feelings of attachment to the child, depressive states, sexual dysfunction, deterioration in general well-being, anger, irritability, feeling of emptiness , distrust of everyone around.

Therefore, you need to provide yourself with the most comfortable conditions to maintain the level of oxytocin at the proper level: a relaxing massage, travel, positive emotions, walks, communication with pleasant people, and doing what you love will help.

Vasopressin

Vasopressin or antidiuretic hormone (ADH) is a hormone that is produced as a prohormone in the hypothalamus, then transported to the nerve endings of the posterior pituitary gland, from which it is secreted into the bloodstream when appropriately stimulated. This hormone contains nine amino acids, one of which is arginine. Therefore, this hormone is also called ADH.

What is the hormone vasopressin responsible for? The action of the hormone vasopressin is based on the performance of 2 main functions in the body - regulation of water metabolism and influence on blood pressure. The antidiuretic effect consists of stimulating the processes of water reabsorption in the distal parts of the nephron, due to the effect on specific receptors of the second type. As a result, there is a decrease in fluid excretion and an increase in circulating blood volume. Thus, one of the effects of ADH is to reduce the amount and increase the concentration of urine. This hormone also increases the absorption of water in the intestines. In addition, in slightly higher concentrations, vasopressin increases vascular tone, causing constriction of arterioles, resulting in increased blood pressure. This quality of the hormone is extremely important in adaptation mechanisms during large blood loss and the development of shock, when there is a sharp significant release of antidiuretic hormone into the blood and blood vessels constrict. Also, the release of vasopressin increases with blood thickening, a decrease in the volume of intra- and extracellular fluid, general dehydration, a drop in blood pressure, activation of the sympathetic-adrenal system and the renin-angiotensin system. In addition, ADH is involved in the formation of the feeling of thirst and drinking behavior.

Vasopressin and aldosterone work together and affect the exchange of fluids and salts in the body. Aldosterone and vasopressin and their disturbance can cause alkalosis, acidosis, and edema.

As a neuropeptide, vasopressin is involved in the formation of long-term memory, facilitates the consolidation and restoration of memory, participates in the formation of biological rhythms, in the formation of emotional behavior, as well as in the antinociceptive, that is, analgesic, system.

With insufficient amounts of vasopressin, a disease such as diabetes insipidus develops. This produces excessive amounts of low-density urine. The amount of fluid released can reach 25 liters per day, causing severe dehydration. Among the causes of this disease are neuroinfections, traumatic brain injuries, hypothalamic tumors, and cerebral strokes in the hypothalamic region.

With an excessive amount of vasopressin, on the contrary, urine excretion is significantly reduced, and water is retained in the body. This disease is called Parhon syndrome and is extremely rare. Such patients are worried about excruciating headaches, increased weakness, lack of appetite, nausea and vomiting, and weight gain.

It is worth considering that the level of the hormone vasopressin decreases in the lying position, and increases in sitting and standing positions. Therefore, when taking blood for analysis of the hormone vasopressin, it is important to take into account the patient’s position. In addition, the level of the hormone depends on the time of day (the ADH concentration is lower during the day than at night).

Purpose of pancreatic hormones

With the help of this body endocrine as well as exocrine secretion is ensured. Moreover, the second type of secretion of enzymes that are present in digestive tract, is reproduced by the main part of the pancreas. Endocrine function is carried out due to the islets of Langerhans - small-sized secreting cells. Their number does not exceed 2% of the total volume of the gland. Islets are made up of certain types of cells. With their help, the following important hormones are produced:

• with the help of PP cells, pancreatic polypeptide is formed;
• D cells are required for the formation of somatostatin;
• B cells are responsible for the production of insulin;
• A cells are necessary for the synthesis of glucagon.

The role of insulin

The action of this biologically active substance is very important for the normal functioning of the entire organism. It helps regulate glucose levels in the body. This process involves a large number of other mechanisms that also take part in minimizing glucose. Among them are the following:

1. Glycolysis or the process of enhanced oxidation of glucose. This mechanism is observed in liver cells, with the interaction of the enzymes pyruvate kinase, glucokinase, and phosphofructokinase. Under the influence of insulin, these substances are activated. When triggering increased breakdown of glucose, the above enzymes will help reduce its concentration.
2. Increasing the process of glucose permeability in cell membranes. In this case, special receptors are activated in cell membranes. Moreover, this effect is achieved not by enhancing their work, but by increasing the number of these receptors.
3. Gluconeogenesis or suppression of the process of converting certain substances into glucose. In this case, the action is aimed at suppressing certain enzymes by insulin. The process of gluconeogenesis occurs in liver cells. There, with the participation of vasopressin, angiotensin, corticoid hormones, as well as glucagon, the process of producing glucose produced from non-carbohydrate components occurs. In this case, not only insulin inhibits the above biologically active substances, but also a simultaneous decrease in the activity of the liver enzyme, which plays a major role in the synthesis of glucose.
4. An increase in the amount of glucose contained in the form of glycogen is achieved with the help of glucose-6-phosphate. This process is observed in muscle tissue, as well as in liver cells.

In addition to the above processes, the following processes are activated:

1. Cell proliferation increases.
2. The absorption of proteins by cells increases. This process is quite important for muscle cells that need amino acids.
3. The process of converting carbohydrates into fats is enhanced. In the future, insulin will promote the flow of certain enzymes to this adipose tissue. With their help, the subcutaneous fat layer will be built. These deposits can be concentrated both in the subcutaneous tissue and on various organs.
4. The formation of proteins and DNA in cells is stimulated. Under the influence of insulin, the breakdown of these substances slows down.
5. The process of permeability of cell walls to phosphates, magnesium, and potassium increases.

However, along with the processes described above, opposite actions also occur:

1. The level of lipolysis is noticeably reduced. With it, there is not sufficient breakdown of fats necessary for further absorption of these components into the blood.
2. The level of protein hydrolysis decreases. In this case, there is a decrease in the flow of broken down protein particles into the blood.

Role of glucagon

This biologically active substance is opposite in action to insulin. Its formation is not limited by the action of A cells. This hormone is also capable of reproducing other cells concentrated in gastrointestinal tract. It is worth noting that 40% of this substance is produced by the pancreas. Under the influence of this hormone, the following processes occur in the body:

1. Formation of glucose from non-carbon components.
2. Increased lipid breakdown, which occurs when these compounds are concentrated in adipocytes. In this case, the amount of lipase enzyme in fat cells increases, due to which there is a subsequent flow of components of the fat breakdown process into the blood. In the future, they can serve as a reserve of additional energy.
3. Activation of the process of decomposition of existing glycogen in muscles, as well as in liver cells. With its help, the process of glucose formation starts.

Experts say that this hormone is necessary to trigger mechanisms aimed at increasing blood glucose levels. Since the body constantly regulates various processes, the opposite effect of this hormone is exerted by somatostatin. Under its influence, insulin production decreases. This substance is produced not only in the pancreas, but also in the hypothalamus. Its active action contributes to:

• delayed absorption of sugars from food;
• inhibition of the reproduction of digestive enzymes;
• decrease in the amount of glucagon;
• decreased activity of hydrochloric acid production, as well as gastrin production;
• significant decrease in circulating blood volume in abdominal cavity;
• reducing the rate of further transfer of stomach contents into the intestines.

The role of pancreatic polypeptide

This substance, like the cells that produce it, was discovered by specialists relatively recently. It is worth noting that it is produced only in the pancreas. The effect of this hormone has not yet been fully studied. Nevertheless, scientists note stimulation of its production when eating fats, as well as glucose and proteins. However, the introduction of these substances intravenously does not increase it.

Among its main functions, experts highlight:

• ability to suppress action pancreatic enzymes involved in digestion;
• the ability to relax the muscles of the gallbladder;
• the ability to stop the release of bilirubin, bile, and trypsin.

The action of this polypeptide is aimed at economical consumption of digestive enzymes. This hormone controls excess bile consumption, which is necessary for proper digestion. Therefore, it can be argued that the pancreas, along with its biological active substances, have a huge impact on the vital functions of the whole organism.

Once again I decided to talk about the hormone vasopressin. The concentration of vasopressin in the blood is higher in men than in women, which is one of the factors determining the characteristics of a man’s character. It is vasopressin that gives a man confidence, the desire to dominate and control “his” territory, and is involved in the formation of attachments.

These conclusions were made by scientists who studied the biology and behavior of voles. They found an inverse relationship between vasopressin levels and the tendency of males to engage in polygamy. The higher the determined indicator, the more “domestic” the animal’s behavior was. Scientists believe that a man’s behavior is similarly dependent on the content of this hormone.

Vasopressin and oxytocin

Vasopressin, together with another hormone produced by the hypothalamus, oxytocin, are “adherents” of the so-called attachment, which often replaces passionate feelings. Passion is usually caused not only by the undoubted merits of a woman, but also by an increase in the level of norepinephrine and dopamine in a man’s blood, synthesized by the adrenal glands. Thus, vasopressin with oxytocin on the one hand and dopamine with norepinephrine on the other are peculiar antipodes that determine a man’s behavior in relationships.

Effects of vasopressin on attachment

It’s not hard to guess that not everything is so simple, and other hormones can interfere with the harmonious transition from crazy love to tender feelings. For example, testosterone causes aggression, the desire to conquer and move on, reducing the activity of vasopressin and.

Men whose testosterone levels are high are not inclined to get married, and once married, they often get divorced. Although in some situations testosterone is defeated - for example, when a man picks up a child. This event causes an intense release of oxytocin and vasopressin.

Of course, the level has a significant impact on the behavior of partners, and therefore on the relationship in a couple. However, this is only nature’s way of creating conditions for the emergence of a family. A lot also depends on the people themselves. The emotional and sexual intimacy that appeared in the first months of communication on the wave of dopamine should not disappear, and for this, the so-called “neurotransmitters of tenderness” alone are not enough.

You need to be able to discuss your desires and problems, voice them and hear your partner, make efforts to maintain trust and affection, if necessary.

The pituitary gland is an important part endocrine system. The pituitary gland is located in the brain and consists of two lobes: anterior and posterior. The anterior part is called the adenohypophysis, the posterior part is called the neurohypophysis. The neurohypophysis synthesizes two important hormones - vasopressin and oxytocin (the functions of other substances secreted by the neurohypophysis are unknown).

Neurohypophysis hormones

As stated above, vasopressin and oxytocin are two active hormones produced by the neurohypophysis. Vasopressin constricts blood vessels, providing an increase in blood pressure if necessary. Its second name is antidiuretic hormone (ADH) because it regulates water exchange the body by increasing the concentration of urine and reducing its excreted volume.

Oxytocin gets its name from its ability to stimulate the smooth muscles of the uterus, which is important in some situations during childbirth.

The importance of vasopressin for the body

Vasopressin, or antidiuretic hormone (ADH), seriously affects the water balance in the body. Its increased secretion can lead to decreased diuresis (urine output).

Physiologically, the functions of vasopressin are as follows:

• increased tubular reabsorption of water;
• decrease in the amount of sodium ions in the blood;
• increased blood circulation volume;
• a general increase in the amount of fluid in the tissues.

Impact on muscle tone, in particular on the tone of the smooth muscles of the uterus, is another of the functions of vasopressin. This effect is due to an increase in the tone of small arteries and capillaries.

Important! According to some studies, antidiuretic hormone plays an important role in the processes of learning and memory formation, in the formation of behavioral reactions.

Secretion of vasopressin into the blood

The secretion of ADH into the blood is determined by the influence of two factors: firstly, the sodium content in the body and, secondly, the volume of blood circulation. An increase in the former and a decrease in the latter will cause increased ADH release, as these are signs of high fluid loss (dehydration).

With normal functioning of the neurohypophysis, the amount of antidiuretic hormone secreted by it is sufficient to maintain fluid homeostasis in the body. Injuries, painful shock, severe blood loss - these conditions cause a massive injection of antidiuretic hormone into the circulatory system.

Note. The same condition of the neurohypophysis is caused by a number of medical supplies and certain mental disorders.

Deficiency and excess of vasopressin

A decrease in the amount of vasopressin in the blood can lead to diabetes insipidus. This disease causes inhibition of the function of water reabsorption in the renal tubules, which leads to a very large urine output - up to 20 liters per day. Moreover, the consistency of urine is close to the consistency of blood plasma.

Extreme thirst, dryness oral cavity and skin are constant companions of diabetes insipidus. Dehydration of the body leads to a decrease in blood pressure, sudden weight loss and depression of central nervous system functions.

The reasons for decreased ADH secretion may be:

• head injuries;
• hemorrhages in the pituitary tissue;
• neurohypophysis cyst;
• meningitis;
• encephalitis;
• heredity;
• radiation therapy in the treatment of brain tumors.

It is often not possible to identify the cause of diabetes insipidus; in such cases, a decrease in the release of antidiuretic hormone is called idiopathic. Treatment of diabetes insipidus is carried out by an endocrinologist using drugs containing artificial ADH.

An excess of ADH in the blood can indicate the presence of such a rare disease as Parhon syndrome. Its main manifestations:

• blood plasma density is much lower than normal;
• low levels of sodium ions in the blood;
• concentrated urine.

With Parhon's syndrome, symptoms are expressed by the patient's weight gain, weakness, constant nausea, low urine volume, migraines and loss of appetite. Complications can lead to swelling of the brain and decreased vital signs, which in turn can cause coma or death.

The reasons for this increase in vasopressin secretion may include some types of lung cancer, cystic fibrosis, pathologies respiratory tract and brain, intolerance to certain drugs. To reduce the high secretion of antidiuretic hormone, vaptans (ADH antagonists) are used.

The main functions of the hormone oxytocin

The particular influence of this hormone is due to the following areas:

• female reproductive system;
• condition of the walls of blood vessels and muscle tissue;
• psycho-emotional sphere.

The production of the hormone and the amount of its secretion by the neurohypophysis depends on many factors.

Stimulation of the area around the female nipple, sexual intercourse and orgasm, massage, periodic pain, physical activity, feeding a child with breast milk, childbirth increases the amount of oxytocin in a woman’s blood. Moreover, at night the hormone level is higher than during the day.

The effect of oxytocin in the male body has not been studied enough. It is believed that it may be an antagonist of ADH.

Effect on childbirth and lactation

The effect of oxytocin on the body during lactation and childbirth is the most studied functional area of ​​this hormone. It is his work that determines the tone of the myometrium (muscle fibers of the uterus) in the third trimester of pregnancy. First, under the influence of the hormone, “training” of the uterine muscles begins - complementary contractions, and during childbirth there are already full-fledged contractions. It is the influence of oxytocin that determines the onset of contractions and, directly, childbirth, mainly at night.

The influence of the hormone on the postpartum period is expressed in the work to restore the normal size of the uterus. Thanks to contractions of muscle fibers, bleeding and accompanying inflammation are eliminated.

Note. To help childbirth and promote the speedy recovery of a woman’s body in the postpartum period, in some cases a synthetic form of the hormone oxytocin is used. To this day, it is considered the most popular drug when it is necessary to cause uterine contractions.

As you know, prolactin affects the process of milk production in women. The activity and duration of lactation depends on the amount of lactotropic hormone. But the direct activity of milk secretion from the breast is controlled by the hormone in question. When feeding begins, oxytocin is automatically injected into the blood from the neurohypophysis. When it reaches the mammary glands, milk begins to be released. If oxytocin secretion is impaired or too low, feeding will be difficult, regardless of the amount of prolactin.

Sex and the emotional component of relationships

Oxytocin has significant effects on sex life and, in particular, on the occurrence of orgasm. Increasing its amount has a beneficial effect on intimate life and libido levels in men. Women, thanks to it, experience more intense sensations during sex. The influence of oxytocin is not limited only to physical manifestations; it is responsible for the psychological component of partner relationships.

Mental and other effects

Recent studies show a link at the genetic level between the amount of the hormone in the blood and autism. If the information about positive impact oxytocin on emotions and recognition of loved ones, drugs based on it can be used in the treatment of patients with autism.

Interesting. The influence of hormone levels has also been noticed in the sphere of social communication. When its quantity decreases, character traits such as greed, distrust, and unfriendliness become more acute.

Oxytocin has a beneficial effect on muscle fibers. An increase in the level of the hormone in the blood triggers the processes of rejuvenation of aging muscles. Statistics show that in areas with long-livers, the concentration of oxytocin in the blood of people is higher. In addition, oxytocin inhibits the increase in stress hormones.

Thus, it is difficult to overestimate the importance of neurohypophysis hormones in the activities of the human body.

Antidiuretic hormone (ADH) is a hormone of the hypothalamus.

Functions of vasopressin

– increases the reabsorption of water by the kidney, therefore increasing the concentration of urine and reducing its volume. It is the only physiological regulator of water excretion by the kidney.

– a number of effects on blood vessels and the brain.

– along with corticotropin-releasing hormone, stimulates the secretion of ACTH.

The final effect of vasopressin on the kidneys is an increase in body water content, an increase in circulating blood volume and dilution of blood plasma.

– increases smooth muscle tone internal organs, especially the gastrointestinal tract, vascular tone, causes an increase in peripheral resistance. Due to this, it increases blood pressure. However, its vasomotor effect is small.

– has a hemostatic effect due to spasm of small blood vessels and increased secretion of some blood clotting factors from the liver. The development of hypertension is facilitated by an increase in the sensitivity of the vascular wall to the constrictor effect observed under the influence of ADH. catecholamines. In this regard, ADH received the name.

– In the brain, it is involved in the regulation of aggressive behavior. It is assumed to be involved in memory mechanisms

– Arginine-vasopressin plays a role in social behavior: in finding a partner, paternal instinct in animals and paternal love in men.

Connection with oxytocin

Vasopressin is chemically very similar to oxytocin, so it can bind to oxytocin receptors and through them has an effect that stimulates tone and contractions of the uterus. The effects of vasopressin are much weaker than those of oxytocin. Oxytocin, binding to vasopressin receptors, has a weak vasopressin-like effect.

The level of vasopressin in the blood increases during shock, trauma, blood loss, pain syndromes, psychosis, and when taking certain medications.

Diseases associated with impaired vasopressin functions.

Diabetes insipidus

In diabetes insipidus, the reabsorption of water in the collecting ducts of the kidneys decreases.

Syndrome of inappropriate antidiuretic hormone secretion

The syndrome is accompanied by increased urine output and problems with the blood. Clinical symptoms- lethargy, anorexia, nausea, vomiting, muscle twitching, convulsions, coma. The patient's condition worsens when large volumes of water enter the body, remission occurs when water consumption is limited.

Vasopressin and social relationships

In 1999, using the example of voles, the following property of vasopressin was discovered. Steppe voles belong to 3% mammals with monogamous relationships. When prairie voles mate, oxytocin and . If the release of these hormones is blocked, sexual relations between prairie voles become as fleeting as those of their “dissolute” mountain relatives. It is blocking that brings the greatest effect.

Rats and mice recognize each other by smell. Scientists suggest that in other monogamous animals and humans, the evolution of the reward mechanism involved in the formation of attachment proceeded in a similar way, including for the purpose of regulating monogamy.

Among the great apes studied, vasopressin levels in the brain's reward centers monogamous monkeys was higher than that of non-monogamous rhesus monkeys. The more receptors there are in areas associated with reward, the more pleasure the social interaction brings.

An alternative hypothesis is that voles' monogamy is caused by changes in structure and abundance. dopamine receptors .

Vasopressins they are formed only in mammals.

Arginine-vasopressin is formed in representatives of most classes of mammals, and lysine vasopressin- only in some artiodactyls - domestic pigs, wild boars, American pigs, warthogs and hippopotamuses.

The system for regulating social behavior and social relations is associated with neuropeptides - oxytocin And .

These neuropeptides may work and how neurotransmitters(transmit a signal from one neuron to another individually), and how neurohormones(excite many neurons at once, including those located far from the point of neuropeptide release).

Oxytocin and vasopressin- short peptides consisting of nine amino acids, and they differ from each other by only two amino acids.

In all animals studied, these peptides regulate social and sexual behavior, but the specific mechanisms of their action may vary greatly among animals. different types.

In snails homologue of vasopressin and oxytocin regulates oviposition and ejaculation. In vertebrates, the original gene was duplicated, and the two resulting neuropeptides diverged: oxytocin affects females more than males.

Oxytocin regulates the sexual behavior of females, childbirth, lactation, attachment to children and marriage partners.

Vasopressin affects erection and ejaculation in a variety of species, including rats, humans, and rabbits, as well as aggression, territorial behavior, and relationships with wives.

If a virgin rat is injected into the brain, it begins to care about other people's rat pups, although in its normal state it is deeply indifferent to them. On the contrary, if a mother rat suppresses the production oxytocin or block oxytocin receptors, she loses interest in her children.

If in rats oxytocin causes concern for children in general, including strangers, then in sheep and people the situation is more complicated: the neuropeptide ensures selective attachment of the mother to her own children.

In voles, which are characterized by strict monogamy, females become attached to their chosen one for life under the influence of oxytocin. Most likely, in this case, the previously existing oxytocin system formation of attachment to children was “co-opted” to form unbreakable marital bonds. In males of the same species, marital fidelity is regulated, as well as .

The formation of personal attachments appears to be one aspect of a more general function oxytocin- regulation of relationships with relatives. For example, mice with the oxytocin gene disabled stop recognizing conspecifics they previously met. Their memory and all senses work normally.

Introduction vasotocin(avian homologue of vasopressin) to male territorial birds makes them more aggressive and makes them sing more, but if the same neuropeptide is administered to male zebra finch, which live in colonies and do not protect their areas, then this does not happen. Apparently, neuropeptides do not create a type of behavior out of nothing, but only regulate existing behavioral stereotypes and predispositions.

It is much more difficult to study everything in humans - who would allow experiments to be carried out with people. However, much can be understood without gross intervention in the genome or brain.

When men are given vasopressin in their noses, other people's faces appear less friendly to them. In women, the effect is the opposite: other people’s faces become more pleasant, and the subjects themselves’ facial expressions become more friendly (in men, on the contrary).

Experiments with administration have so far been carried out only on men (it is more dangerous to do this with women, since oxytocin strongly affects the female reproductive function). It turned out that oxytocin improves the ability of men to understand the mood of other people by facial expression. In addition, men begin to look their interlocutor in the eyes more often.

In other experiments, an effect was found to increase gullibility. Men injected with oxytocin appear to be more generous in the “game of trust.”

According to researchers, society may soon face a whole series of new “bioethical” problems. Should traders be allowed to spray in the air around their goods? oxytocin? Is it possible to prescribe oxytocin drops to quarreling spouses who want to save the family?

The hormone vasopressin binds one person to another, and this is a useful quality. Let there be more of it.)))))))