Vasopressin mechanism of action. Antidiuretic hormone (vasopressin, ADH): what kind of hormone is it, what is it responsible for, tests

Structure

It is a peptide consisting of 9 amino acids with a half-life of 2-4 minutes.

Synthesis

It is carried out in the supraoptic and paraventricular nuclei of the hypothalamus. From here, vasopressin is sent to the secretion point (the posterior lobe of the pituitary gland) in the form of a prohormone, consisting of two parts - ADH itself and neurophysin. During transportation, processing occurs - hydrolysis of proADG into the mature hormone and neurophysin protein.

Regulation of synthesis and secretion

Reduce: ethanol, glucocorticoids.

Activate:

• excitation osmoreceptors in the hypothalamus and in the portal vein of the liver due to an increase in plasma osmolarity during dehydration, renal or hepatic failure, accumulation of osmotically active substances(glucose),
• activation baroreceptors heart and carotid sinus with a decrease in blood volume in the vascular bed (blood loss, dehydration),
• emotional and physical stress,
• nicotine, angiotensin II, interleukin 6, morphine, acetylcholine,

In adulthood and old age, the number of osmoreceptors decreases. Consequently, the sensitivity of the hypothalamus to increased osmolarity decreases and the likelihood of chronic dehydration.

Regulation of secretion and effects of antidiuretic hormone

Mechanism of action

Depends on receptors:

1. Calcium-phospholipid mechanism, coupled

• with V 1 receptors of smooth muscles of arterioles, liver, platelets,
• with V 3 receptors of the adenohypophysis and brain structures.

2.Adenylate cyclase mechanism - with V 2 receptors of the renal tubules.

Targets and effects

Kidneys

Increases the reabsorption of water in the epithelial cells of the distal tubules and collecting ducts, due to the “exposure” of water transport proteins – aquaporins – to the membrane:

• through the adenylate cyclase mechanism causes phosphorylation aquaporin molecules (only type 2, AQP2), their interaction with microtubule proteins and, by exocytosis, the incorporation of aquaporins into the apical membrane,
• stimulates by the same mechanism aquaporin synthesisde novo.

Vascular system

Supports stable pressure blood, stimulating vascular tone:

• increases smooth muscle tone skin vessels, skeletal muscles and myocardium (to a lesser extent),
• increases mechanoreceptor sensitivity in the carotid sinuses to changes in blood pressure,

Other effects

Metabolic effects

Excessive amounts of vasopressin in the blood:

• in hungry animals activates glycogenolysis in the liver, which causes the release of glucose into the blood,
• in well-fed animals in the liver stimulates glycolysis, which here is the beginning of the synthesis of TAG and cholesterol,
• enhances glucagon secretion,
• reduces the lipolytic effect of catecholamines in adipose tissue,
• enhances the secretion of ACTH and, consequently, the synthesis of glucocorticoids.

In general, the effect of vasopressin on the hormonal and metabolic status of the body comes down to: hyperglycemia And lipid accumulation.

Brain

• participates in mechanisms memory and behavioral aspects of stress,
• through V 3 receptors stimulates secretion in corticotrophs ACTH And prolactin,
• increases pain threshold sensitivity,
• increased concentrations of vasopressin and vasopressin/oxytocin imbalance are observed in depression, anxiety, schizophrenia, autism, and personality disorders. In the experiment, vasopressin causes in rats aggressive behavior and anxiety.

Bone

Supports bone structure renewal and mineralization by enhancing the activity of both osteoblasts and osteoclasts.

Vascular system

Affects hemostasis, generally increasing blood viscosity:

• in the endothelium causes the formation von Willebrand factor, antihemophilic globulin A(coagulation factor VIII) and tissue plasminogen activator(t-PA),
• in the liver also increases synthesis factor VIII coagulation,
• enhances aggregation and degranulation platelets.

Pathology

Hypofunction

Appears as diabetes insipidus (diabetes insipidus– tasteless diabetes), the incidence is approximately 0.5% of all endocrine diseases. Manifested by a large volume of urine up to 8 l/day, thirst and polydipsia, dry skin and mucous membranes, lethargy, irritability.

There are different causes of hypofunction:

1. Primary Not diabetes– ADH deficiency due to impaired synthesis or damage to the hypothalamic-pituitary tract (fractures, infections, tumors);

2. Nephrogenic diabetes insipidus:

• hereditary - impaired reception of ADH in the kidney tubules,
• acquired – kidney disease, damage to the tubules by lithium salts in the treatment of patients with psychosis.

3. Progestational(during pregnancy) – increased breakdown of vasopressin arginine aminopeptidase placenta.

4. Functional– temporary (in children under one year old) increase in phosphodiesterase activity in the kidneys, leading to disruption of the action of vasopressin.

Hyperfunction

Inappropriate secretion syndrome– when the hormone is formed by any tumors, in diseases of the brain. There is a risk of water intoxication and dilutional hyponatremia.

Vasopressin is one of the hormones of the hypothalamus. It is formed in the magnocellular neurons of this part of the brain. Vasopressin is then transported to the neurohypophysis, where it accumulates.

The role of vasopressin in the body

The main effect of vasopressin is on water metabolism. Another name for this substance is antidiuretic hormone (ADH). Indeed, an increase in vasopressin concentration leads to a decrease in the volume of urine excreted (diuresis).

The main biological action of ADH:

• increased water reabsorption;
• decreasing sodium levels in the blood;
• an increase in blood volume in the vessels;
• an increase in the total volume of water in body tissues.

In addition, antidiuretic hormone affects the tone of smooth muscle fibers. This effect is manifested by an increase in vascular tone (arterioles, capillaries) and blood pressure.

It is believed that ADH is involved in intellectual processes (learning, memory) and forms some forms social behavior (family relationships, paternal attachment to children, control of aggressive reactions).

Release of ADH into the blood

The antidiuretic hormone accumulated in the neurohypophysis is released into the blood under the influence of two main factors: an increase in the concentration of sodium and other ions in the blood and a decrease in the volume of circulating blood.

Both of these conditions are manifestations of dehydration. For early detection of life-threatening fluid loss, special sensitive receptor cells exist. An increase in plasma sodium concentration is detected by osmoreceptors in the brain and other organs. And low blood volume in the vessels is detected by volume receptors in the atria and intrathoracic veins.

Normally, the antidiuretic hormone vasopressin is released in sufficient quantities to maintain the constancy of the internal fluid environment of the body.

Especially a lot of vasopressin enters the vascular bed during injuries, pain, shock, and massive blood loss. In addition, certain medications and mental disorders can trigger the release of ADH.

Vasopressin deficiency

Insufficient levels of ADH in the blood lead to the development of central diabetes insipidus. With this disease, the function of water reuptake in the renal tubules is inhibited. A lot of urine is released. Diuresis per day can reach 10–20 liters. Characteristic feature is low specific gravity urine, which is almost equal to the specific density of blood plasma.

Patients with diabetes insipidus suffer from severe thirst, constant dry mouth, dry skin and mucous membranes. If a patient is deprived of the opportunity to drink water for any reason, he quickly develops dehydration. The manifestation of this condition is a sharp loss of body weight, a decrease in blood pressure (less than 90/60 mm Hg), dysfunction of the central nervous system. nervous system.

Diabetes insipidus is diagnosed using urine, blood, and Zimnitsky tests. In some cases, it is necessary to restrict fluid intake for a short period of time while monitoring blood composition and urine density. Analysis for vasopressin is not very informative.

The cause of decreased secretion of antidiuretic hormone may be a genetic predisposition, traumatic brain injury, meningitis, encephalitis, hemorrhage into functional tissue, a tumor of the pituitary gland or hypothalamus. This disease often develops after surgical or radiation treatment of brain tumors.

Quite often the cause of diabetes insipidus cannot be determined. This decrease in ADH secretion is called idiopathic.

Treatment of the central form of diabetes insipidus is carried out by an endocrinologist. Synthetic antidiuretic hormone is used for therapy.

Excessive secretion of vasopressin

Excessive secretion of the hypothalamic hormone vasopressin occurs in Parhon syndrome. This is a fairly rare pathology.

The syndrome of inappropriate secretion of antidiuretic hormone (Parhon's syndrome) is manifested by low blood plasma density, hyponatremia, and the release of concentrated urine.

Thus, excess ADH provokes loss of electrolytes and water intoxication. Under the influence of vasopressin, water is retained in the body, and trace elements leave the bloodstream.

Patients are concerned about low urine output, weight gain, severe weakness, convulsions, nausea, loss of appetite, headache.

In severe cases, coma and death occur as a result of cerebral edema and depression of vital functions.

The cause of inadequate secretion of antidiuretic hormone is some forms of cancer (in particular, small cell lung tumor), cystic fibrosis, bronchopulmonary pathology, and brain diseases. Parhon's syndrome may be a manifestation of individual intolerance to certain medications. For example, it can be provoked by opiates, barbiturates, non-steroidal drugs, psychotropic medications, etc.

Treatment of excess levels of antidiuretic hormone is carried out with vasopressin antagonists (vaptans). It is important to limit the volume of liquid you drink to 500–1000 ml per day.

Several organisms can maintain fluid balance along with electrolytes at the same time. Among them, the antidiuretic hormone of the hypothalamus or other vasopressin, which is responsible for the regulatory factor, stands out.

Purpose of the hormone

Among neurohormones important has antidiuretic hormone. The production of vasopressin is initially noticeable in the hypothalamus, after which it appears in the posterior lobe of the pituitary gland, accumulation of the hormone occurs and a slight delay in its output.

When it reaches a certain level, the hormone begins to pass into the blood. After vasopressin penetrates the pituitary gland, a stimulating effect on the work of ACTH occurs, on which the work of the adrenal glands depends.

Functions

Vasopressin plays an important role in the human body, but it is not multifunctional. In contrast to the hormones located in the posterior lobe, a more extensive effect is observed in the hormones of the anterior lobe of the pituitary gland, they are called somatotropin, as well as prolactin and ACHT. The hormone vasopressin has the main functions: thanks to this, fluid is properly released through the kidneys, and the volume of collected urine is regulated.

The hormone has a beneficial effect on blood vessels and the processes occurring in them, helping the functioning of the brain. Antidiuretic hormone affects muscles internal organs, it increases blood pressure and blood clots faster. One of the functions of vasopressin is to improve memory and maintain psychological processes.

Causes, deviations from the norm of antidiuretic hormone

Hypofunction occurs for various reasons:

• One of the problems is the emergence of primary diabetes insipidus. In this disease, synthesis is disrupted and ADH deficiency is observed. The cause may be damage to the hypothalamic-pituitary tract, this includes fractures and tumors, as well as infections.
• The second reason is nephrogenic diabetes insipidus. With this disease, there is a manifestation of a hereditary type and an acquired one.
• Reason number three is gestagenic, it manifests itself during pregnancy. In this case, there is an increased breakdown of the hormone vasopressin.
• The next one is functional or in other words temporary. Basically, it noticeably manifests itself in a child who is less than a year old. At this time, there is an increase in activity in the kidneys, which disrupts the functioning of vasopressin.

One of the main reasons why there is a decrease in the secretion of antidiuretic hormone is a genetic predisposition, possibly trauma to the cerebral cortex and brain damage.

Sometimes, vasopressin decreases after meningitis or encephalitis, often after a tumor of the pituitary gland or hypothalamus. After surgical or radiation treatment of tumors that have appeared in the brain, the disease begins to develop.

Hyperfunction

If the hormone is formed after the appearance of a tumor or during the onset of brain diseases, inappropriate secretion syndrome is formed. Against the background of this phenomenon, water intoxication appears, in some cases even dilutional hyponatremia.

Normal quantity in the table

The value of the hormone vasopressin and its normal values ​​depend on the level of plasma osmolarity. ADH of 1.5-5 ng/l is observed when an osmolarity of 275-290 mosmo/l appears. Exercise testing will help establish an accurate investigation of diabetes insipidus, as well as Parhon's syndrome.

How and why to conduct tests

Analyzes must be carried out in order for the diagnosis to establish accurate indicators. During the study, diagnostic drugs are used to examine the level of sodium in the blood and also in the urine. In addition, diagnostics are necessary to detect the osmolarity of blood, urine and at what stage the level of vasopressin is. The procedure includes an MRI and a CT scan of the brain. The skull is checked and x-rays are taken; in addition, it is important to examine the kidneys.

Excessive amount of hormone

With the formation of Parhon's syndrome, an excessive increase in the hypothalamic hormone vasopressin is observed. This phenomenon applies to rare species pathology. The appearance of the syndrome of inadequate secretion of antidiuretic hormone contributes to the formation of low density of blood plasma; in addition, the urine comes out in high concentration, and hyponatremia is observed.

Because of large quantity ADH causes significant loss of electrolytes as well as water intoxication. In the body, fluid stops its spread under the influence of vasopressin; the hormone affects microelements that leave the bloodstream.

Diuresis in small quantities begins to bother patients, the body increases in mass, severe weakness is felt, convulsions are observed, the patient feels nauseous, loses appetite and even has a headache.

There are severe cases when a sick person falls into a coma, resulting in a fatal outcome as a result of cerebral edema.

Inappropriate secretion of antidiuretic hormone occurs after some types of cancer or diseases such as cystic fibrosis or pulmonary bronchopulmonary pathology. Possibly with the onset of brain diseases.

Hormone deficiency

If an insufficient amount of ADH is found in the body, the central form of a disease such as diabetes insipidus develops. During this disease, a reuptake function is observed in the renal tubules. A large amount of urine is released, which reaches 10-20 liters per day. Among the main features, the low specific density stands out; it is basically no different from the density of blood plasma.

Patients develop excessive thirst; during the manifestation of diabetes insipidus, dry mouth is observed, the skin and mucous membranes also become dry. If you refuse to drink plenty of fluids, dehydration begins. During illness there is a sharp loss of weight, arterial pressure decreases, the functioning of the central nervous system is disrupted.

The presence of diabetes insipidus can be determined by urine tests, as well as blood tests and Zimnitsky tests. You should avoid drinking a lot of fluids for some time; during this period, the condition of the blood and the density of the urine are observed. Only an endocrinologist is able to determine correct treatment central form of diabetes insipidus. To carry out therapy, it is necessary to use a synthetic antidiuretic hormone.

Antidiuretic hormone production

The first name of this hormone is vasopressin. It is produced by cells of the supraoptic and paraventicular nuclei of the hypothalamus. Many people think that it comes from the pituitary gland. After synthesis has occurred, the hormone combines with a carrier protein. After formation, the complex is sent to the posterior lobe of the pituitary gland, where the hormone accumulates. Vasopressin is released for several reasons:

• Changes in blood pressure levels.
• The amount of blood in the patient's body.

Special cells respond to osmolarity, which appears from changes in electrolyte composition. The cells are located in the periventricular regions of the hypothalamus. The hormone begins to be released after a change in blood osmolarity, at which time it leaves the endings of neurons and enters the blood.

Norm

In humans, the normal amount of plasma osmolarity can be determined; it should not exceed the limits of 282-300 mosmo/kg. Starting from 280 mosmo/kg at osmolarity, the release of ADH is observed. If a person drinks a lot of fluid, the secretion of the hormone is suppressed. Vasopressin is released when the level increases above 295 mosmo/kg, and the patient begins to feel the need to drink. In this case healthy body tries to protect itself from excess moisture loss.

There is a special formula that makes it easy to calculate plasma osmolarity:

2 x +glucose + urea + 0.03 x total protein, resulting in osmolarity.

The amount of blood changes depending on how the secretion of antidiuretic hormone changes. During heavy blood loss, thanks to receptors located in the left atrium of the heart, a signal enters the neurohypophysis and in this case vasopressin is released.

Release of ADH into the blood

Under the influence of two main factors, antiliuretic hormone is released directly into the blood, which has accumulated in the neurohypophysis. All this occurs from an increase in the concentration of sodium, as well as other ions entering the blood. In addition, from a decrease in the amount of circulating blood.

Due to this condition, dehydration of the body occurs. To detect moisture loss earlier, you need to pay attention to special sensitive cells. Thanks to osmoreceptors in the brain, as well as other organs, the plasma sodium concentration increases. A low amount of blood in the vessels can be detected using the volume receptors of the atria, as well as the internal veins.

To maintain the internal fluid environment in the patient's body, antidiuretic hormone must be produced in normal quantities. During injuries and pain syndromes, vasopressin is released into the vascular bed in large quantities. This amount of hormone is observed with heavy blood loss. ADH release occurs from mental disorders and from the influence of certain types of medications.

Where to check antidiuretic hormone

Radioimmunoassay can be used to detect ADH in the blood. It is considered the most common method. In addition, it is necessary to determine the osmolarity of blood plasma. Each endocrinology center checks tests to detect pathology. It is necessary to place a certain amount of blood in a test tube and not add preservatives. Before taking tests, you must take a break of 10-12 hours from eating food and only then donate blood for the presence of the hormone.

The result will be inaccurate and unreliable if there were mental and physical stress on the eve of the test. It is not recommended to engage in hard work before taking the test, and also to refuse sports competitions; it is best not to take exams.

Those drugs that can increase hormone levels should not be used. If absolutely necessary for any reason, you should write on the referral form about the drug used and its quantity. The actual level of ADH changes under the influence of certain medications:

• sleeping pills;
• estrogens;
• anesthetics;
• tranquilizers;
• oxytocin;
• morphine;
• carbamazeline.

All of the above remedies must be taken after appointment by a specialist and examination of the body.

Treatment

To get rid of excess amounts of antidiuretic hormone, it is necessary to use antagonists, they are called vaptans. During the day during the detection of the disease, it is necessary to maintain the level of fluid consumed. You should not drink less than 500-1000 ml of water.

The hormone vasopressin does not have many different functions, but if its secretion is disrupted, diseases can occur. To prevent the development of diseases, it is recommended to visit a specialist and have your body examined at least 1-2 times a year.

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Vasopressin is a hormone that is produced in neurons of the hypothalamus. Vasopressin is then sent to the neurohypophysis, where it accumulates. Antidiuretic hormone (another name for vasopressin) regulates the removal of fluid from the kidneys and normal brain function.

ADH structure

This hormone contains nine amino acids, one of which is arginine. That is why in the literature you can find another name for ADH - arginine vasopressin.

In its structure, vasopressin is very close to oxytocin. That is, if the chemical connection between glycine and arginine in ADH is broken, the biological action of vasopressin will change. Besides, high level ADH can cause uterine contractions, and high levels of oxytocin have an antidiuretic effect.

The production of vasopressin affects the volume of fluid that fills the vessels and cells of the body, as well as the sodium content of the cerebrospinal fluid.

Vasopressin is also a hormone that indirectly increases body temperature.

Vasopressin (hormone): functions

The main function of this hormone is to control water metabolism in the body. Indeed, an increase in ADH concentration leads to an increase in diuresis (that is, the amount of urine excreted).

The main role of vasopressin in the body:

• Decrease in the level of sodium cations in the blood.
• Increased reabsorption of fluid (due to aquaporin - a special protein that is produced under the influence of the hormone).
• Increasing the volume of blood circulating in the vessels.
• Increase in the total amount of fluid in tissues.

In addition, ADH affects the tone of smooth muscles, which manifests itself as an increase in the tone of small vessels (capillaries and arterioles), as well as an increase in blood pressure.

An important effect of vasopressin is its participation in the processes of memory, learning and social behavior (attachment of fathers to children, family relationships and control of aggression).

Release of vasopressin into the blood

After the hypothalamus, where vasopressin is produced, the hormone accumulates along the processes of neurons with the help of neurophysin-2 (a special carrier protein) in the neurohypophysis (posterior lobe), and from there, under the influence of a decrease in blood volume and an increase in sodium and other blood ions, the antidiuretic hormone enters the blood.

Both of the above factors are signs of dehydration, and to maintain fluid balance in the body, there are special receptor cells that are very sensitive to lack of water.

The receptors that respond to increased sodium are called osmoreceptors and are located in the brain and other important organs. Low blood volume is recorded by volume receptors located in the atria and intrathoracic veins.

If vasopressin levels are reduced

Insufficient production of the hormone and, accordingly, its low level in the blood leads to the appearance of a complex specific disease called diabetes insipidus.

The main manifestations of the disease are as follows:

• Increasing weakness.
• Increased daily urine output (polyuria) to eight liters or more.
• Dryness of mucous membranes (nose, eyes, stomach, bronchi, mouth and trachea).
• Extreme thirst (polydipsia).
• Irritability, excessive emotionality.

The reasons for the development of this disease may be a lack of vasopressin and the presence of infectious processes in the body. Insufficient supply of the hormone is often a consequence of tumors of the pituitary gland or hypothalamus, as well as kidney disease, which manifests itself in changes in the regulation and synthesis of vasopressin.

Another reason for this pathological condition Pregnancy may occur, during which arginine, which is part of the hormone, is destroyed.

Diabetes insipidus can be caused by:

• Meningitis.
• Encephalitis.
• Genetic predisposition.
• Brain hemorrhages.
• Radiation therapy of tumors.

If the cause of the disease is not determined, then diabetes insipidus is called idiopathic.

An endocrinologist treats patients with this pathology. The main drug for the treatment of diabetes insipidus is synthetic vasopressin.

When assessing its level, it must be remembered that the amount depends on the time of day (that is, during the day the concentration of ADH is lower than at night). The position of the patient when taking blood for analysis is also important: in the lying position, the level of vasopressin decreases, and in the sitting and standing position it increases.

If vasopressin is elevated

Excessive production of ADH is rare and is called Parhon's syndrome. The syndrome of excessive secretion of vasopressin is characterized by hyponatremia, decreased density of blood plasma, and the release of concentrated urine.

That is, due to increased hormone production, water intoxication and massive loss of electrolytes develop (fluid accumulates in the body, and trace elements are removed from it).

Patients with this pathology complain of:

• Decreased diuresis and small amount of urine excreted.
• Rapid weight gain.
• Cramps.
• Increasing weakness.
• Nausea.
• Headache.
• Loss of appetite.

In severe cases, the patient falls into a coma and dies, which is a consequence of suppression of vital body functions and cerebral edema.

The causes of Parhon's syndrome may be:

• Some neoplasms (for example, small cell lung tumors).
• Brain diseases.
• Cystic fibrosis
• Bronchopulmonary pathologies.

One of the provoking factors in the development of this condition may be the use of certain medications (if they are intolerant) NSAIDs, barbiturates, opiates, psychotropics, and so on.

Therapy for Parhon syndrome comes down to the prescription of vasopressin antagonists (vaptans), as well as limiting the amount of fluid consumed to half a liter per day.

Vasopressin. Hormone in pharmacology

In pharmaceutical practice, ADH is used as a drug that increases fluid reabsorption in the kidneys, reduces diuresis and is the main drug in the treatment of diabetes insipidus.

Antidiuretic hormone analogues: minirin, desmopressin, terpipressin, desmopressin.

The structure of the hormone makes it possible to produce preparations based on it in the form of aqueous, oily solutions and lipressin.

Methods of application

Most effective means Desmopressin is recognized for the treatment of diabetes insipidus. It reduces urine production at night. If a patient has venous bleeding from the esophagus, injectable forms of vasopressin are used for treatment..

An aqueous solution of ADH is administered both intramuscularly and intravenously.

Synthetic vasopressin (hormone) is given at a dose of five to ten units every twenty-four to thirty-six hours. If bleeding from the gastrointestinal tract occurs, the dosage changes: vasopressin is administered intravenously every minute in an amount of 0.1-0.5 units.

ADH analogues

Synthetic drugs (analogs of vasopressin) "Lysinvasopressin" and "Minirin" are prescribed intranasally. Indications for the use of these medications are: enuresis, diabetes insipidus, hemophilia and neoplasms of the hypothalamus and pituitary gland. Spray the preparations every four hours, two units into each nostril.

If enuresis is present, Desmopressin is prescribed in the form of nasal drops. This drug quickly penetrates the blood and spreads throughout the body. The effect occurs within thirty minutes after administration.

To reduce blood flow and blood pressure (blood pressure), Terlipressin is prescribed. Due to the fact that in this drug the structure of vasopressin is changed (that is, arginine is replaced by lysine and glycine residues are added), this medicine has a powerful vasoconstrictor effect.

The drug is prescribed as an intravenous injection, the effect appears within half an hour after administration. Terlipressin is indicated for operations on the gastrointestinal tract and pelvis, as well as for bleeding from the digestive organs and gynecological operations.

Antidiuretic hormone (ADH, Vasopressin), quantitative analysis

Antidiuretic hormone (ADH) or vasopressin is a hormone secreted by the pituitary gland (the central organ of the endocrine system, located on the lower surface of the head...

Unfortunately, this analysis is not available in your region.

Find this analysis elsewhere locality

Description of the study

Preparing for the study:

2-4 weeks in advance, in agreement with the attending physician, you should stop taking medications that may affect the results of the study (diuretics, antihypertensive (lowering blood pressure) drugs, oral contraceptives, licorice drugs);

10-12 hours before the analysis, it is necessary to limit physical activity and refuse to eat;

Before taking blood, the patient needs to lie down for 30 minutes and relax.

Test material: Taking blood

Antidiuretic hormone (ADH) or vasopressin is a hormone that is secreted by the pituitary gland (the central organ of the endocrine system, located on the lower surface of the brain).

Its main role in the body is to regulate water metabolism. Vasopressin stimulates the reverse flow of fluid across the membranes of the renal tubules, i.e. carries out water retention in the body. Along with the regulation of water metabolism, it controls the osmotic pressure of the blood plasma.
A lack of antidiuretic hormone leads to diabetes insipidus, a disease characterized by the release of extremely large quantities fluids with urine. The main symptoms of diabetes insipidus are polyuria (increased urine production) and polydipsia (pathologically increased thirst).
Diabetes insipidus develops due to insufficient production of vasopressin (central form) or the inability of the kidneys to adequately respond to vasopressin circulating in the blood due to insensitivity of the renal tubules to this hormone (renal form). In the renal form of diabetes insipidus, ADH deficiency is called relative, and its concentration in the blood plasma is increased or normal.

Diabetes insipidus in pregnant women (gestational diabetes mellitus) is associated with increased activity of the placental enzyme vasopressinase, which destroys ADH. This form of diabetes insipidus is temporary and stops after childbirth.
When excess vasopressin is produced by the hypothalamus, the syndrome of inappropriate vasopressin production or Parhon's syndrome occurs. Parhon's syndrome is the most common variant of impaired ADH production, characterized by a decrease in sodium content in the blood, plasma hypoosmolarity, oliguria (decreased urine output), lack of thirst, the presence of general edema, and weight gain. The patient is worried about headache, lack of appetite or decreased appetite, nausea, vomiting, muscle weakness, drowsiness or insomnia, painful muscle spasms, tremor (shaking) of the limbs. This condition occurs with injuries to the skull and brain, circulatory disorders, congenital malformations, inflammatory diseases of the central nervous system, such as meningitis, encephalitis, polio, etc.

A significant increase in ADH content, which contributes to the development of Parhon's syndrome, can also be caused by some malignant tumors, such as lung cancer, lymphosarcoma, pancreatic cancer, Hodgkin's lymphoma, prostate cancer, etc., which themselves are capable of synthesizing vasopressin. In addition, non-tumor diseases of the lungs often lead to an increase in ADH: pneumonia caused by staphylococcus, tuberculosis, lung abscess, sarcoidosis.

The test determines the concentration of antidiuretic hormone (ADH) in the blood plasma (pg/ml or pmol/l) and plasma osmolality (mosm/kg or mosm/l).

Method

One of the most highly sensitive and highly specific methods for determining hormones in blood serum is the RIA method (radioimmunoassay). The essence of the method is that a serum containing the desired substance (ADG) and an excess of the same substance (ADG) in a known concentration, labeled with radionuclides (radioactive isotopes), is applied to a special binding system (with a limited number of binding sites). Excess ADH and ADH from the sample (blood serum) competitively bind to the binding system, forming specific complexes (labeled and unlabeled). The number of labeled complexes is inversely proportional to the amount of unlabeled (desired) substance in the sample and is measured using special devices - radio spectrometers.

The osmolarity of blood plasma can be determined by cryoscopy, i.e., by the freezing point of the solution. Units of measurement are mOsm/kg or mOsm/L.

Reference values ​​- norm
(Antidiuretic hormone (vasopressin, ADH), blood)

Information regarding the reference values ​​of indicators, as well as the composition of the indicators included in the analysis, may differ slightly depending on the laboratory!

Norm:

Indications

Diagnosis of diabetes insipidus;
- diagnosis of tumors of the APUD system (ectopically producing vasopressin).

Increasing values ​​(positive result)

Increased ADH secretion is observed in the following conditions:

Acute intermittent porphyria;

Brain tumor (primary or metastases);

Pneumonia;

Tuberculous meningitis;

Pulmonary tuberculosis;

Renal diabetes insipidus.

Malignant bronchogenic lung cancer;

Hodgkin's lymphoma;

Prostate cancer;

Malignant tumors of the pancreas, thymus, duodenum.

An increase in ADH concentration is also observed at night, when moving to a vertical position, during pain, stress or physical activity, with increased plasma osmolality (for example, with the administration of a hypertonic solution), with a decrease in effective blood volume and hypotension.