Wazopresyna (AVP)

Proven content

Vasopressin is an antidiuretic hormone that is produced in the hypothalamus. It works by the kidneys to reduce the amount of water that is produced into the urine. This leads to the passing of less and more concentrated urine. In addition, vasopressin constricts blood vessels and increases blood pressure. The stimuli stimulating the release of vasopressin are: a drop in blood pressure and a decrease in the volume of circulating blood.

Vasopressin – characteristics

Vasopressin (an anti-diuretic hormone) is a hormone secreted by the pituitary gland (back lobe) that regulates urine density and blood pressure. There is a reduction in glomerular filtration in the kidneys, which results in urine concentration and reduction of its presence. The reabsorbed water allows it to increase the volume of circulating blood, effectively increasing blood pressure. At the same time, vasopressin causes the walls of blood vessels to contract. Another function of vasopressin is to regulate the aggregation of platelets, as well as to normalize the process of gluconeogenesis in the liver. The concentration of vasopressin depends on hormones such as adrenaline, cortisol and sex hormones. The production of vasopressin occurs under the influence of such stimuli as:

1. drop in blood pressure
2. decrease in circulating blood volume,
3. increase in plasma osmolarity.

Vasopressin deficiency as well as excess hormone is dangerous to health. Synthetic vasopressin, i.e. desmopresynais used as a medicine, e.g. in diabetes insipidus. Pain or stress may be responsible for too high levels of vasopressin in the blood. Too high a concentration of vasopressin can induce the so-called Schwartz-Bartter syndromewhich leads to the retention of excess water, while the level of electrolytes in the blood drops significantly (mainly sodium). In addition, vasopressin is produced in greater amounts during sleep, when blood pressure drops. On the other hand, its reduced level is observed in people who consume alcohol excessively.

Summary of Vasopressin (AVP) Function:

1. is responsible for the density of urine and blood pressure,
2. is involved in the production of TSH (thyroid hormone),
3. stimulates the production of cortisol,
4. regulates the aggregation of platelets (leads to the release of von Willebrand factor and factor VIII from them),
5. stimulates the secretion of growth hormone (GH),
6. participates in the body’s thermoregulation process (e.g. biological rhythm or feeling of thirst).

When do we do the vasopressin test?

The most common indications for the examination.

1. Suspicion of diabetes insipidus (passing large amounts of uncompressed urine).

2. Suspicion of Schwartz-Bartter syndrome (associated with excessive secretion of vasopressin).

3. Electrolyte disturbances – hyponatremia.

Material for vasopressin testing: serum.

Preparation for the test: on an empty stomach (at least 8 hours).

The course of the study: one-time blood sampling from the ulnar vein and determination of vasopressin concentration.

Time to wait for the result: 1 Day.

Standard: 1,85-7,4 pmol / L (2-8pg / ml). Interpretation of results should only be made when the molality of the plasma is known.

Comments: The analysis of the result is possible provided that the current plasma molality is known (the correct value is 280-295 mmol / kg water).

Diagnostics related to abnormal amounts or effects of vasopressin may also include dehydration tests and dehydration-vasopressin. The first one is carried out during hospitalization. The patient cannot take any fluids for several or even several hours. During this abstinence, the osmolality and specific gravity of urine as well as the osmolality and the amount of sodium in the blood are analyzed. If, despite the cessation of fluid intake, the patient continues to excrete uncompressed urine, diabetes insipidus is suspected. Then it is necessary to determine what type of diabetes insipidus is, and for this purpose a supplement to the dehydration test is performed.

In turn, in the dehydration-vasopressin test, he gives the patient desmopresynę, that is, an analogue of vasopressin. If the urine specific gravity and osmolality continue to increase despite the administration of the substance, central diabetes insipidus may be suspected, for which vasopressin deficiency is typical. However, if, despite the administration of desmopressin, the urine parameters have not changed and are still outside the norm – nephrogenic diabetes insipidus in which there is a defect of renal receptors is suspected.

Excess vasopressin

Too high concentration of vasopressin Schwartz-Bartter syndrome often responds. This ailment causes the body to retain excess water, while the level of electrolytes in the blood drops significantly. The symptoms of the syndrome vary greatly, especially in the early stages. With the development of the disease, the following occurs:

1. excessive irritability,
2. nausea,
3. excessive water retention in the body,
4. vomiting
5. mood swings,
6. in some cases, mental disorders,
7. lowering muscle tone,
8. in advanced stages of convulsions and coma.

To confirm this disease, a blood test is required to check the level of sodium, potassium chloride and osmolality.

The release of vasopressin in excessive amounts causes the symptoms called YES, i.e. a syndrome of inadequate secretion of vasopressin. It is diagnosed with hyponatremia, i.e. low sodium level in the blood, increased sodium excretion in the urine and decreased blood osmolarity. The most common cause of this syndrome is:

1. lung cancer
2. gastrointestinal cancer,
3. carcinoid,
4. epilepsy,
5. thymoma,
6. a brain tumor,
7. brain trauma,
8. meningitis,
9. encephalitis,
10. Guillain-Barré syndrome, HIV infection and the development of AIDS,
11. multiple sclerosis,

The cause of high levels of antidiuretic hormone may also be right heart failure and hydrocephalus. In some people, it may also be caused by surgeries in the pituitary or hypothalamus. On the other hand, drugs that cause too high a concentration of vasopressin are: anti-cancer drugs, anti-epileptics, anti-depressants, desmopressins, vasopressins and non-steroidal anti-inflammatory drugs.

High levels of vasopressin caused by a drop in blood sodium levels are manifested by:

1. headaches and dizziness,
2. nausea
3. feeling tired
4. disturbed consciousness,
5. coma,
6. convulsions
7. sometimes even breathing stops due to brain swelling.

Vasopressin deficiency

Vasopressin deficiency causes diabetes insipidus. The symptoms of this ailment are increased thirst and excessive urine production. Diabetes insipidus is rare, but it can occur in pregnant women. Normally, in a healthy person, excess fluid is excreted by the kidneys as urine, due to the regulation of vasopressin that is released into the bloodstream and thickens the urine.

One type of diabetes insipidus is gestational diabetes insipidus. The cause of its occurrence is the destruction of vasopressin by the enzyme produced by the placenta in the mother’s body. Nephrogenic urethra, on the other hand, is caused by a defect in the renal tubules, which do not respond properly to the presence of hormones. Diarrhea can also occur as a result of excessive fluid intake, when the mechanism responsible for the feeling of thirst has been disturbed.

In addition to the symptoms of excessive thirst (polydipsia) and increased urine production, diabetes insipidus also presents:

1. constipation
2. sweating hands,
3. fatigue,
4. excessive loss of water from the body,
5. higher temperature.

Treatment of vasopressin secretion disorders

Compulsive (compulsive) drinking of water should be considered in the diagnosis in people with a deficiency or lack of vasopressin effect. In this situation, low vasopressin levels are physiological.

Depending on the type of disorders (excessive secretion or deficiency of vasopressin), preparations having an effect analogous to this hormone are administered. A synthetic substance in the form has a similar effect desmopresyny. It reduces diuresis and is administered to people suffering from diabetes insipidus and central diabetes insipidus. Another preparation is terlipresynawhich has the greatest effect on the blood vessels because it causes the smooth muscle cells to contract. Works well in stopping bleeding.

Vasopressin antagonists are waptany, i.e. substances used in the treatment of liver cirrhosis, heart failure and hyponatremia.

Desmopressin as a drug

In the treatment of some diseases, desmopressin, a synthetic analogue of vasopressin, is used. Its benefits are seen in the treatment of ailments such as:

1. hemophilia type A,
2. nocturnal polyuria,
3. diabetes insipidus,
4. von Willebrand disease (mild form).

Moreover, desmopressin is used in the vasopressin test. However, there are some contraindications to the use of this substance, e.g. SIADH syndrome, circulatory failure, hyponatraemia, renal failure and psychogenic polydipsia.

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