Interesting Facts About The Hormone Vasopressin

In this article you will learn some important information about the antidiuretic hormone. It is also called vasopressin. Its main function is to regulate the activity of the kidneys. But it also has a certain influence on the cardiovascular system and the central nervous system, among other things.

Vasopressin is also known as antidiuretic hormone, or ADH. It is formed in the brain, more precisely in the hypothalamus, and from there it is released via the pituitary gland (pituitary gland). After all, that’s how it gets into the blood. As an “antidiuretic” hormone, it helps to preserve body fluids. Because it controls the amount of water that the kidneys excrete.

The hormone is an oligopeptide that is formed by the union of 9 amino acids. The amino acids that make up this hormone are: cysteine, tyrosine, glutamine, proline, an amino group, phenylalanine, arginine, asparagine, and a carboxyl group.

Function of vasopressin

As mentioned at the beginning: The main function of this hormone is to regulate the activity of the kidneys. It regulates the water and electrolyte balance in the body. But it also has a certain influence on the cardiovascular system and the central nervous system, among other things.

This hormone is released as a reaction to a lack of water in the organism or a reduction in blood volume. Certain receptors register this fact and these in turn trigger the release of vasopressin into the blood. In the kidneys, the hormone causes fluid to be reabsorbed (so-called ‘reabsorption’). This then normalizes the body’s water balance.

As a result of the mechanism of reabsorption in the kidneys, i.e. the recovery of water from the urine, the amount of urine decreases and its concentration increases. When vasopressin is released in high concentrations, it can lead to an increase in blood pressure. Because it causes a slight narrowing of the vessels.

What are the effects of the hormone?

On the kidneys

In the kidneys, the hormone improves a number of processes used to concentrate urine. And because vasopressin promotes the concentration of the urine, it causes the above-mentioned reabsorption of water.

The main effects of vasopressin on the kidneys are three main ones :

• It increases the water permeability of the collecting ducts of the kidneys. In addition, it increases the water permeability of the outer and inner kidney canals. In this way, water is reabsorbed and urine is excreted in a higher concentration.
• In addition, the hormone increases the permeability of the inner section of the manifold to the urea.
• Increased sodium intake through the so-called Henle’s loop.

Effects on the central nervous system

Vasopressin is also involved in regulating blood pressure and temperature. And there is evidence that this hormone can have pain relieving effects. These depend on the one hand on gender and on the other hand on the stress level.

Effect on the vessels

Vasopressin also has a strong constricting effect on the blood vessels  and can therefore greatly increase the systemic vascular resistance. This also explains the original name of the hormone. Because the name vasopressin refers precisely to this vasoconstricting effect at higher doses. It comes from the Latin vas (blood) vessel and pressus (pressure).

How is the hormone regulated?

The release of vasopressin is usually controlled by the osmolarity of the extracellular fluids. Decreased osmolarity reduces the secretion of the hormone. While increased osmolarity increases the release.

Receptors in the heart and large blood vessels detect low blood pressure or a decrease in blood volume. This happens in the case of bleeding or dehydration. In these circumstances, they stimulate the release of vasopressin.

The release of the antidiuretic hormone also occurs when the concentration of salts in the bloodstream increases. If the concentration of salts is abnormally low, it is hyponatremia. This means that the sodium level in the blood is too low.

The hormone is also released through thirst, nausea, vomiting and pain. In this way, it ensures that the volume of fluid in the circulatory system is maintained in the event of stress or injury.

What happens if there is an excess of vasopressin?

High levels of the antidiuretic hormone cause the kidneys to retain water in the body. This can lead to a disease called Schwartz-Bartter syndrome. But it is also called syndrome of inadequate ADH secretion (SIADH).

Too much vasopressin is released in people with this syndrome when it is not needed. This causes the kidneys to retain excessive amounts of water. The result is a thinning of the blood and a characteristically low salt concentration.

An excessive release of vasopressin can be caused, for example, by side effects of certain drugs, or by diseases of the lungs, the chest wall, the hypothalamus or the pituitary gland.

What if my vasopressin levels are too low?

A low level of this hormone causes the kidneys to excrete too much water. The amount of urine increases, leading to dehydration and a drop in blood pressure. Such low vasopressin levels can indicate damage to the hypothalamus or pituitary gland. However, it could also be a sign of primary polydipsia.

Conclusion

Vasopressin is an excellent therapeutic alternative in the daily practice of intensive care medicine, both alone and in combination with other agents.