Hormones are chemical compounds which, when released from the endocrine glands into the blood or nervous system of living things, exert modulatory effects on the functions of other cells and structures in the body.
One of the most relevant and well-known human hormones is vasopressin or antidiuretic hormone, which is essential for water retention or stress response, among other phenomena. In this article we will analyze the properties and functions of vasopressin.
What is vasopressin?
Vasopressin is also known as “Argipressin”, “arginine vasopressin” and “antidiuretic hormone”. As the latter name suggests, this hormone performs functions related to the reabsorption of water molecules by the kidneys and the decrease in the amount of urine accumulated in the body.
It is an oligopeptide, that is to say a molecule composed of the union of a small number of amino acids, namely 9. On the other hand, polypeptides are groups of between 10 and 100 amino acids, whereas we speak of “proteins” to designate clusters of more than 100 molecules of this type.
Specifically, vasopressin contains an amino group (-NH2), cysteine (Cys), tyrosine (Tyr), phenylalanine (Phe), glutamine (Gln), asparagine (Asn), proline (Pro) , arginine (Arg) and a carboxyl group (-COOH).
Vasopressin is secreted by the neurohypophysis, The posterior lobe of the pituitary gland, in response to changes in osmotic concentration and blood volume. Although most of the vasopressin we make is released into the bloodstream, its effects on the brain also explain some of its functions.
Other pituitary hormones
The pituitary or pituitary gland is one of the main endocrine glands. It performs an intermediary function between the hypothalamus, which initiates the secretion of hormones, and the rest of the endocrine system by sending biochemical signals.
This structure is made up of two lobes: the anterior or adenohypophysis and the posterior or neurohypophysis. While the posterior pituitary gland stores the hormones vasopressin and oxytocin (related to motherhood and orgasm), the adenohypophysis secretes thyrotropin-releasing hormones, corticotrophin, gonadotropins and growth hormone.
Functions of this hormone
The main functions of vasopressin are associated with their ability to regulate renal activity; however, this hormone also has effects on other bodily systems, including the cardiovascular system and the central nervous system.
1. Fluid retention and reabsorption
Vasopressin increases the permeability of kidney cells, increasing the amount of water they absorb; this function is called “antidiuresis”. Such a process also involves an increase in the concentration of urine due to the reduced availability of fluid in the excretory system.
On the other hand, the antidiuretic hormone also reabsorbs urea, the main chemical compound in urine, which is made up of body wastes. This prevents the frequency of urination from being excessive.
2. Maintenance of homeostatic balance
Homeostasis (self-regulation of the internal environment of organisms) depends on a large number of factors; among these is the activity of vasopressin. If homeostatic mechanisms fail, they can cause problems such as dehydration and acidosis.
This hormone helps maintain the electrolyte balance in the bloodstream by retaining and reabsorption of adequate amounts of water, glucose and sodium, Among other chemical compounds relevant to the functioning of the body.
3. Increased blood pressure
Another major effect of vasopressin is the increase in blood pressure. This function results from the vasoconstrictor properties of this hormone, which have a moderate intensity. The enhancing role of vasopressin on hormones and neurotransmitters associated with stress it is also important to explain this effect.
4. Modulation of the stress response
Although scientific research has not yet fully confirmed this, there is strong evidence that vasopressin has a modulating effect on the body’s response to stressful (or anxious) situations.
Antidiuretic hormone regulates the release of corticotropin releasing hormone, also called “corticotropin releasing hormone”. This compound promotes secretion of corticosteroids such as aldosterone and cortisol, Associated primarily with vasoconstriction and adrenal gland stress response.
5. Reduction of the sensation of pain
In recent years, the involvement of vasopressin in the modulation of painful sensations has started to be studied. One thinks that this hormone could act as a pain reliever; this would imply that, when released under certain conditions, vasopressin would have reinforcing effects due to the positive sensations associated with its secretion.
6. Formation of sexual and social bonds
Rodent studies suggest that the release of vasopressin also acts as a reinforces social bonds, especially those of a couple. In humans, these effects have been found mainly in humans and are linked to the direct release of the antidiuretic hormone in the reward circuits of the central nervous system.