Functions of the antidiuretic hormone vasopressin. Vasopressin (hormone): functions and role in the body. Antidiuretic hormone

Antidiuretic hormone (ADH) is a protein substance that is formed in the hypothalamus. Its main role in the body is to maintain water balance. ADH binds to special receptors located in the kidneys. As a result of their interaction, fluid retention occurs.

Some pathological conditions are accompanied by impaired hormone production or changes in sensitivity to its effects. With its deficiency, diabetes insipidus develops, and with its excess, the syndrome of inappropriate ADH secretion develops.

Characteristics and role of the hormone

The precursor to antidiuretic hormone (or vasopressin) is produced in the neurosecretory nuclei of the hypothalamus. By shoots nerve cells it is transferred to the posterior lobe of the pituitary gland. During transport, mature ADH and the protein neurophysin are formed from it. Secretory granules containing the hormone accumulate in the neurohypophysis. Vasopressin partially enters the anterior lobe of the organ, where it participates in the regulation of the synthesis of corticotropin, which is responsible for the functioning of the adrenal glands.

Hormone secretion is controlled through osmo- and baroreceptors. These structures respond to changes in fluid volume and pressure in the vascular bed. Factors that increase the production of vasopressin include stress, infections, bleeding, nausea, pain, human chorionic gonadotropin, severe lesions lungs. Its production is affected by taking certain medications. The concentration of ADH in the blood depends on the time of day - at night it is usually 2 times higher than during the day.

Medicines that affect the secretion and action of the hormone:

Regulation of secretion and effects of vasopressin

Vasopressin, together with other hormones - atrial natriuretic peptide, aldosterone, angiotensin II, controls water-electrolyte balance. However, the importance of ADH in the regulation of water retention and excretion is leading. It helps maintain fluid in the body by reducing urine output.

The hormone also performs other functions:

• regulation of vascular tone and increased blood pressure;
• stimulation of the secretion of corticosteroids in the adrenal glands;
• influence on blood coagulation processes;
• synthesis of prostaglandins and release of renin in the kidneys;
• improving learning ability.

Mechanism of action

At the periphery, the hormone binds to sensitive receptors. The effects of vasopressin depend on their type and location.

Types of ADH receptors:

The structural and functional unit of the kidney, in which plasma filtration and urine formation occurs, is the nephron. One of its components is the collecting duct. It carries out the processes of reabsorption (reabsorption) and secretion of substances that allow maintaining water-electrolyte metabolism.

Action of ADH in the renal tubules

The interaction of the hormone with type 2 receptors in the collecting ducts activates a specific enzyme - protein kinase A. As a result, the number of water channels - aquaporins-2 - increases in the cell membrane. Through them, water moves along an osmotic gradient from the lumen of the tubes into the cells and extracellular space. It is assumed that ADH enhances the tubular secretion of sodium ions. As a result, the volume of urine decreases and it becomes more concentrated.

In pathology, there is a disruption in the formation of the hormone in the hypothalamus or a decrease in the sensitivity of receptors to its action. Lack of vasopressin or its effects leads to the development of diabetes insipidus, which is manifested by thirst and increased urine volume. In some cases, it is possible to increase the production of ADH, which is also accompanied by water and electrolyte imbalance.

Diabetes insipidus

For diabetes insipidus stands out a large number of diluted urine. Its volume reaches 4–15 or more liters per day. The cause of the pathology is an absolute or relative deficiency of ADH, as a result of which the reabsorption of water in the renal tubules decreases. The condition may be temporary or permanent.

Patients note an increase in the amount of urine - polyuria, and increased thirst - polydipsia. With adequate fluid replacement, other symptoms do not bother you. If water losses exceed its intake into the body, signs of dehydration develop - dry skin and mucous membranes, weight loss, drop in blood pressure, increased heart rate, increased excitability. Age specific feature in older people there is a decrease in the number of osmoreceptors, so in this group the risk of dehydration is greater.

Exist following forms diseases:

• Central- is caused by a decrease in the production of vasopressin by the hypothalamus due to injuries, tumors, infections, systemic and vascular diseases affecting the hypothalamic-pituitary zone. Less commonly, the cause of the condition is an autoimmune process - hypophysitis.
• Nephrogenic- develops due to a decrease in the sensitivity of renal receptors to the action of ADH. In this case, diabetes is hereditary or occurs due to benign hyperplasia prostate, sickle cell anemia, following a low-protein diet, taking lithium medications. The pathology can be provoked by increased excretion of calcium in the urine - hypercalciuria, and low potassium content in the blood - hypokalemia.
• Primary polydipsia- occurs with excessive fluid consumption and is psychogenic in nature.
• Diabetes insipidus in pregnancy- a temporary condition associated with increased destruction of vasopressin by an enzyme synthesized by the placenta.

To diagnose diseases, functional tests with fluid restriction and the administration of vasopressin analogues are used. During these tests, the change in body weight, the volume of urine excreted and its osmolarity are assessed, the electrolyte composition of the plasma is determined, and a blood test is taken to study the concentration of ADH. Research is carried out only under medical supervision. If a central form is suspected, an MRI of the brain is indicated.

Treatment of the pathology depends on its course. In all cases, it is necessary to consume a sufficient amount of fluid. To increase the level of vasopressin in the body in case of central diabetes, hormone analogues are prescribed - Desmopressin, Minirin, Nativa, Vazomirin. The drugs selectively act on type 2 receptors in the collecting ducts and enhance water reabsorption. In the nephrogenic form, the root cause of the disease is eliminated; in some cases, prescription is effective. large doses Desmopressin, use of thiazide diuretics.

Antidiuretic hormone is a peptide consisting of 9 amino acid residues. It is synthesized as a prohormone in hypothalamic neurons, the bodies of which are located in the supraoptic and paraventricular nuclei. The gene for antidiuretic hormone also encodes neurophysin II, a carrier protein that transports antidiuretic hormone along the axons of neurons that terminate in the posterior lobe of the pituitary gland, where the accumulation of antidiuretic hormone occurs. Antidiuretic hormone has circadian rhythm secretion (its increase is observed at night). The secretion of the hormone decreases in the supine position, when moving to vertical position its concentration increases. All of these factors must be taken into account when assessing research results.

Reference values ​​for the concentration of antidiuretic hormone in blood plasma

The release of antidiuretic hormone from storage vesicles is regulated primarily by plasma osmolarity. Average level Normal plasma osmolarity is 282 mOsm/L with deviations in one direction or another up to 1.8%. If plasma osmolarity rises above the critical level (threshold) of 287 mOsm/l, then the release of antidiuretic hormone sharply accelerates, which is associated with the activation of osmoreceptors located on cell membrane supraoptic and paraventricular neurons of the hypothalamus and cells of the carotid sinus on carotid arteries. These receptors are capable of detecting changes in osmolarity in the blood plasma of the order of 3-5% higher average size, especially with sudden changes (more than 2% per hour). A rapid increase in plasma osmolarity by only 2% leads to a 4-fold increase in the secretion of antidiuretic hormone, while a decrease in osmolarity by 2% is accompanied by a complete cessation of antidiuretic hormone secretion.

Hemodynamic factors also have a pronounced regulatory effect on the secretion of antidiuretic hormone. A decrease in mean arterial pressure and/or "effective" plasma volume of less than 10% can be detected by baroreceptors located in the cells of the left atrium and, to a lesser extent, in the carotid sinus. Along the multisynaptic afferent pathway, impulses from the “stretched” baroreceptors transmit information to the neurons of the supraoptic and paraventricular nuclei of the hypothalamus, which stimulate the release of antidiuretic hormone.

The main biological effect of antidiuretic hormone is to increase the resorption of free water from urine located in the lumen of the distal part of the renal tubules into the tubular cells. Antidiuretic hormone binds to specific V2 receptors on outer membrane these cells, causing activation of adenylate cyclase, which forms cAMP. cAMP activates protein kinase A. Protein kinase A phosphorylates proteins that stimulate the expression of the gene for aquaporin-2, one of the proteins that creates water channels. Aquaporin-2 migrates to inner surface membranes of tubular cells, where it is embedded in the membrane, forming pores or channels through which water from the lumen of the distal tubules freely diffuses into the tubular cell. Water then passes from the cell through channels in the plasma membrane into the interstitial space, from where it enters the vascular bed.

Diabetes insipidus (antidiuretic hormone deficiency). True diabetes insipidus is characterized by polyuria and polydipsia as a result of antidiuretic hormone deficiency. Persistent diabetes insipidus is caused by destruction of the supra-visual and periventricular nuclei or transection of the supra-optic tract above the median eminence.

The cause of the disease can be damage to the neurohypophysis of any origin. Most often these are tumors - craniopharyngomas and gliomas of the optic nerve. In patients with histiocytosis, diabetes insipidus develops in 25-50% of cases. Occasionally, diabetes insipidus is caused by encephalitis, sarcoidosis, tuberculosis, actinomycosis, brucellosis, malaria, syphilis, influenza, tonsillitis, all types of typhus, septic conditions, rheumatism, leukemia. Diabetes insipidus can develop after a traumatic brain injury, especially if it is accompanied by a fracture of the base of the skull.

Diabetes insipidus developing after surgical interventions on the pituitary gland or hypothalamus, can be either transient or permanent. The course of a disease that occurs after an accidental injury is unpredictable; Spontaneous recovery may occur several years after the injury.

IN last years It has been shown that diabetes insipidus may be of autoimmune origin (the presence of antibodies to ADH-secreting cells). IN in rare cases it may be hereditary. Diabetes insipidus may be a component of the rare Wolfram syndrome, in which it is combined with diabetes mellitus, atrophy optic nerves and sensorineural hearing loss.

Clinical signs of polyuria appear when the secretory capacity of hypothalamic neurons is reduced by 85%. Antidiuretic hormone deficiency can be complete or partial, which determines the degree of polydipsia and polyuria.

A study of the concentration of antidiuretic hormone in blood plasma is not always necessary to diagnose diabetes insipidus. Whole line laboratory parameters quite accurately indicate that the patient has insufficient secretion of antidiuretic hormone. The daily volume of urine reaches 4-10 liters or more, its density ranges from 1.001-1.005, osmolarity ranges from 50-200 mOsm/l. During periods of severe dehydration, urine density increases to 1.010 and osmolarity to 300 mOsm/L. In children initial sign The disease may be nocturia. In other respects, renal function is not impaired. Plasma hyperosmolarity (above 300 mOsm/L), hypernatremia (more than 155 mmol/L) and hypokalemia are often detected. When performing a water restriction test in patients with severe antidiuretic hormone deficiency, an increase in blood plasma osmolarity is observed, but urine osmolarity usually remains lower than plasma osmolarity.

When vasopressin is administered, urine osmolarity rapidly increases. With moderately severe ADH deficiency and polyuria, urine osmolarity during the test may be slightly higher than plasma osmolarity, and the response to vasopressin is weakened.

Constantly low concentrations of antidiuretic hormone in the blood plasma (less than 0.5 pg/l) indicate severe neurogenic diabetes insipidus, subnormal levels (0.5-1 pg/l) in combination with plasma hyperosmolarity indicate partial neurogenic diabetes insipidus. Determining the concentration of antidiuretic hormone in blood plasma is the main criterion for differentiating partial diabetes insipidus from primary polydipsia.

Primary nocturnal enuresis (antidiuretic hormone deficiency). Nocturnal enuresis detected in every tenth child aged 5-7 years, and at the age of 10 years - in every twentieth. Enuresis can be caused by many factors: stress, urogenital infections, nephrological disorders, etc. Quite often, bedwetting is only a consequence of another disease, but in some cases it is caused by primary nocturnal enuresis. This diagnosis is made in children over 5 years of age who, in the absence of organic disorders and normal urination during the day, wet the bed at night more than 3 times a week. A physiological feature of the body of such patients is a low concentration of antidiuretic hormone in the blood. Exists hereditary predisposition to the development of primary nocturnal enuresis. Girls get sick somewhat less often than boys.

Patients with primary nocturnal enuresis produce 2-3 times more urine at night than healthy children. Antidiuretic hormone plays a critical role in this process. Its level in the body constantly fluctuates. U healthy child At night, the concentration of antidiuretic hormone in the blood is higher than during the day, and with primary nocturnal enuresis, this level, already quite low, decreases even more at night, resulting in the formation of a large amount of unconcentrated urine. Usually by four o'clock in the morning, much earlier than in healthy children, the bladder in patients is filled to the limit. Sleep is very deep at this time, so children wet the bed.

Patients with primary nocturnal enuresis are characterized by nocturia, low specific gravity urine in night portions when conducting a test according to Zimnitsky. The osmolarity of urine in night portions is lower than in daytime portions. The concentration of antidiuretic hormone in the blood plasma, when examined during the daytime, is quite often within the normal range, and if a decrease is detected, it is insignificant. Reduced concentrations of antidiuretic hormone in blood plasma are more often detected in the evening and night hours. Prescription for patients with primary nocturnal enuresis synthetic analogues antidiuretic hormone leads to cure in 70-80% of patients.

Nephrogenic diabetes insipidus (diabetes insipidus that is not sensitive to antidiuretic hormone). The disease is based on the lack of sensitivity of the renal tubular epithelium to antidiuretic hormone. When the antidiuretic hormone interacts with the receptors of the renal tubules, cAMP is not formed, therefore protein kinase A is not activated and the intracellular effect of the antidiuretic hormone is not realized. Mostly males are affected. The disease is inherited as an X-linked trait. Changes in laboratory parameters and functional tests are similar to those detected in diabetes insipidus. Nephrogenic diabetes insipidus is characterized by normal or increased concentrations of antidiuretic hormone in the blood plasma. When performing a test with vasopressin, there is no increase in the level of cAMP in the urine after its administration.

In nephrogenic diabetes insipidus, the use of antidiuretic hormone drugs is ineffective. Thiazide diuretics in combination with long-term restriction of table salt in the diet can give good clinical results. It is necessary to correct hypokalemia and hypercalcemia under the control of potassium and calcium concentrations in the blood serum.

Syndrome of inappropriate secretion of vasoporessin (Parhon's syndrome) is the most common variant of impaired secretion of antidiuretic hormone. It is characterized by oliguria (constant or periodic), lack of thirst, the presence of general edema, an increase in body weight and a high concentration of antidiuretic hormone in the blood plasma, inadequate to the level of osmolarity.

This syndrome can develop with pathology of the central nervous system, in particular with meningitis, encephalitis, brain tumors and abscesses, subarachnoid hemorrhages, traumatic brain injuries, and can also be caused by pneumonia, tuberculosis, acute renal failure, psychosis, certain medications (vincristine, carbamazepine, etc.). In some cases, inadequate secretion of antidiuretic hormone is possible with hypothyroidism. The mechanism of impaired secretion of antidiuretic hormone is due to direct damage to the hypothalamus. Sometimes the cause of inadequate secretion of antidiuretic hormone cannot be determined. A decrease in sodium concentration is detected in the blood plasma (less than 120 mmol/l); if it falls below 110 mmol/l, neurological symptoms develop - stupor, convulsions are possible. Plasma osmolarity is low (less than 270 mOsm/l), hypoosmolar coma may develop. When examining 24-hour urine, it is noted increased secretion sodium from the body. Discover increased content antidiuretic hormone in the blood plasma in relation to its osmolarity, reduced concentration of aldosterone, reduced response when conducting a test of inhibition of antidiuretic hormone secretion by water load.

Ectopic secretion of antidiuretic hormone is possible in a wide variety of tumors. Most often, ectopic secretion of antidiuretic hormone accompanies bronchogenic lung cancer, malignant tumors pancreas, thymus glands, duodenum. Changes in laboratory parameters are similar to those in the syndrome of inappropriate secretion of vasoporessin.

Functional state of the renin-angiotensin-aldosterone system

The renin-angiotensin-aldosterone system determines the constancy of the volume and osmolarity of the extracellular fluid. It plays the same role in determining the diameter of blood vessels and the level of tissue perfusion. This cascade [enzyme (renin) - peptide hormone (angiotensin II) - steroid hormone (aldosterone)] performs its important function thanks to the specific ability to detect and return to normal even the slightest increase or decrease in the volume of sodium and water in the body.

The functioning of the renin-angiotensin-aldosterone system can be summarized by the example of its response to reductions in the volume of sodium and water in the body (for example, in the case of bleeding, leading to a decrease in circulating blood volume).

As a result, bleeding is reduced blood pressure in the afferent arterioles of the glomerular glomeruli of the kidneys. Juxtaglomerular cells located in the wall of these arterioles sense the weakening of the arteriolar wall tension, resulting in the release of renin into the glomerular capillary blood.

Renin released into the blood affects angiotensinogen, a plasma protein belonging to the group of α 2 globulins. Angiotensinogen is synthesized and secreted by the liver. Renin cleaves the decapeptide (angiotensin I) from it in the kidneys. Angiotensin I (AI) is a substrate for ACE, which splits off 2 amino acids from it, forming an octapeptide - angiotensin II (AII). Angiotensin II has several effects aimed at correcting the reduced volume of extracellular fluid. One of these actions is to increase the synthesis and secretion of aldosterone in the adrenal glands. Another effect is vasoconstriction of blood vessels. Angiotensin II can be converted into angiotensin III, a heptapeptide that stimulates the secretion of aldosterone by the adrenal glands, and also, like angiotensin II, inhibits the secretion of renin.

Aldosterone causes the reabsorption of sodium and water in the distal tubules of the kidneys (as well as in the distal colon, sweat and salivary glands). This action is aimed at restoring the reduced volume of extracellular fluid. Aldosterone realizes its effects through receptors that are found not only in the kidneys, but also in the heart and blood vessels.

Angiotensin II causes a direct increase in tubular reabsorption of sodium and water in the kidneys, and also has direct vasoconstrictor activity, thereby reducing the volume of the vascular bed, adapting it to the reduced volume of blood plasma. As a result, blood pressure and tissue perfusion are maintained at the right level. Angiotensin II also activates the adrenergic (sympathetic) nervous system, which quickly releases norepinephrine. Norepinephrine also causes vasoconstriction and prevents tissue hypoperfusion. Finally, angiotensin II stimulates the feeling of thirst.

The main function of the renin-angiotensin-aldosterone system is to maintain a constant volume of circulating blood. At the same time, this system plays a leading role in the pathogenesis of renal disease development. arterial hypertension, therefore, in such patients, the study of indicators of the renin-angiotensin-aldosterone system has vital importance in establishing a diagnosis and conducting proper treatment. Renin, angiotensin and aldosterone are functionally closely interrelated in the human body, so it is recommended to simultaneously determine all three indicators.

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

Unfortunately this analysis 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 performing 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.

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 excretion of extremely large amounts of fluid in the 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 shape) or the inability of the kidneys to adequately respond to vasopressin circulating in the blood, due to the 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 defects development, inflammatory diseases central nervous system, such as meningitis, encephalitis, poliomyelitis, 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 glands, 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 introduction hypertonic solution), with a decrease in effective blood volume and hypotension.

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 work brain.

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 ADH ruptures chemical compound between glycine and arginine, biological effect vasopressin will change. In addition, high levels of 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 exchange in organism. 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.
• Promotion total number fluids 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.

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.

Reasons for development of this disease there may be a lack of vasopressin, and the presence infectious processes in organism. 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 the vital functions of the body 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 this state may be taking 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, oil 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, then use injection forms vasopressin.

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 ( arterial 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 drug has a powerful vasoconstrictor effect.

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

Vasopressin is a hormonal substance that regulates the process of removing fluid from the body. This is the only element that performs this function in the human body.

During development various pathologies the synthesis of this hormone may be impaired, leading to uncontrolled diuresis. Let's try to figure out what the hormone vasopressin is, where it is produced and why our body needs it.

Main characteristics and features of vasopressin

First, let's figure out what it is - antidiuretic hormone.

This substance has a protein structure and consists of 9 amino acids. It is destroyed quite quickly (in less than half an hour) in the kidney and liver cells, so the process of its production is regular and cyclical.

Where is it synthesized?

Where is vasopressin produced? ADH is a substance that is synthesized by the cells of the hypothalamus. After this, it penetrates the posterior lobe of the cerebral pituitary gland, where its concentration gradually increases. And only from the pituitary cells is it released into the blood in the required quantity.

It has been proven that the antidiuretic hormone vasopressin is also produced by the gonads, but in limited quantities. However, the essence and purpose of this process still remains unknown.

Main features of the hormone

ADH is a substance that not only has an antidiuretic effect. This element also affects more serious functions of the body. In particular, on the production of ACTH.

The hormone takes part in many processes and affects various organs and systems. For its active production, it must be created special conditions. This could be stress, fear, strong anxiety, gastrointestinal pathologies, accompanied by excessive vomiting or diarrhea, during which the human body loses a large amount of fluid, etc. When water balance is restored, the cells of the hypothalamus gradually reduce the amount of ADH produced to normal limits.

As you can see, antidiuretic hormone is a multifunctional substance that is extremely important for the full functioning of the endocrine system. But its functions are not limited to this, so they should be considered in more detail.

Functional tasks of the ADG

Biological functions vasopressin are:

• stimulating the process of fluid reabsorption in the kidneys;
• reducing the amount of sodium in the body;
• increasing blood volume in blood vessels;
• increasing the volume of water in the body;
• regulation of blood pressure (in particular, the hormone helps to increase it);
• memory stimulation;
• improving learning ability;
• control of social behavior.

These are the main effects of vasopressin, but there are a few more aspects to be aware of. The hormone affects the concentration of urine and reduces its volume. Thus, only the required amount of waste fluid is removed from the body, and all useful substances remain in the cells and tissues. It follows that vasopressin has antidiuretic effect.

In addition, the hormone has hemostatic properties, as it improves blood clotting. This is achieved through spasm blood vessels caused by the activity of this substance. Its production increases significantly in stressful situations, at states of shock, pain syndromes and intense bleeding.

This is interesting. Vasopressin is called the fidelity hormone. And this is quite justified, since when it is sufficiently present in a person’s blood, not only social, but also family behavior is formed. This means that men and women who do not suffer from a deficiency of this substance are more attached to loved ones (especially their spouse) than those whose hypothalamus secretes insufficient amounts of it.

Thus, having studied the mechanism of action of vasopressin and its main tasks in the human body, we can conclude that many important processes occur with its direct participation. Any deviations from the norm may lead to serious disorders, and also signal health problems.

Lack of vasopressin

If the process of hormone secretion is disrupted, ailments occur, which should be the reason for contacting a therapist or endocrinologist. In this case, it is carried out clinical analysis on vasopressin, which may show a decrease or increase in its level.

In addition, it is important to assess the condition of the kidneys, for which a urine test is performed. A biochemical blood test is needed to determine the concentration of potassium, sodium and chlorine in the body. If the test results are alarming, the patient is sent to CT and MRI to clarify the diagnosis.

Reasons for deviations

If, when deciphering research data, hyperfunction of vasopressin was revealed, then often such a violation of its secretion indicates the development pathological processes in organism. One of rare diseases, But common reasons A similar anomaly is Parhon's syndrome. This deviation is also called syndrome of inappropriate secretion of antidiuretic hormone.

This pathology can result from:

• intense bleeding accompanied by large blood losses;
• uncontrolled or long-term use of diuretics;
• hypotension, etc.

Much more dangerous are cases when excess vasopressin is caused by malfunctions of the pituitary gland due to the formation of cancerous tumors. In addition, a jump in indicators is often observed in patients suffering from pulmonary tuberculosis, asthma, and pneumonia. Diseases of the central nervous system can also lead to a similar deviation.

As vasopressin secretion increases, diuresis decreases significantly. Urine becomes darkish, concentrated, and contains increased amount sodium Consequently, its content in the blood decreases, which can lead to serious complications.

Reasons for decreased hormone levels

Decreased ADH secretion is observed in patients with diabetes insipidus. The disease can be triggered by malfunctions of the hypothalamic-pituitary system, as well as a decrease in the sensitivity of renal receptors to the effects of this hormone.

With a lack of vasopressin, severe, difficult to quench thirst, migraine attacks, a sharp decrease in body weight, dry epidermis, viscosity of saliva and a decrease in its volume are observed. frequent urge to vomiting, increased body temperature. The patient exhibits hypotension, so doctors often resort to the use of vasopressors to normalize it.

It is important to pay attention to the amount of urine excreted per day. With ADH deficiency, the urge to urinate sharply increases, and during each emptying of the bladder, a fairly large volume of urine is released. This leads to dehydration and the body loses many useful substances. And this condition is very dangerous and is fraught with serious complications!

How to increase vasopressin?

Methods for normalizing the level of this hormone directly depend on the reasons for its decrease. Removing the tumor, taking antibiotics for infectious etiology diseases, use of drugs to treat pathologies of cardio-vascular system- all these measures may well stabilize the situation and lead to complete cure.

But sometimes it is possible to restore functions and establish the production of the fidelity hormone vasopressin only with lifelong hormone therapy. Specific medications can only be prescribed by a doctor. When developing a treatment regimen, many factors are taken into account that the patient himself cannot take into account. This concerns, first of all, the presence of accompanying chronic diseases(in addition to those that may cause vasopressin deficiency).

Pharmacological agents based on vasopressin are an integral part of the treatment regimen for diabetes insipidus. They help reduce the amount of urine excreted per day, normalizing the functioning of the kidneys.

Thus, having studied the mechanism of action of ADH, determined its main functions and possible reasons deviations, we can conclude that this hormonal substance, along with others, plays important role for coordinated work human body. You cannot ignore any ailments, because if they have a persistent course, this is one of the the brightest signs that serious disruptions have occurred in the human body. Stability hormonal levels– one of the main indicators of health, and this must always be remembered!