Adiuretin is also known as ADH (antidiuretic hormone), vasopressin and AVP (arginine vasopressin). The most common is the name ADH, which is composed of the words "anti" for "contrary" and "diuresis" (urinary excretion). Since the hormone promotes the recovery of water from the kidneys, it works in the opposite direction to urine excretion, which explains the name.
ADH is next to oxytocin as an effect hormone of the hypothalamus. This hormone group acts directly on the cells of the target organs, without taking a detour via body glands. The basic structure of ADH consists of the amino acids phenylalanine, cyctein, arginine, tyrosine, glutamine, asparagine, proline and glycine.
In the human body, adiuretin, together with oxytocin, is formed in the hypothalamus, an area of the diencephalon near the optic nerve. It is then released into the bloodstream.
The amount of ADH that is released is determined by the osmotic concentration of the blood. The water balance of the human body is regulated by osmosis - the balance between the particles of a liquid through a semipermeable membrane. If there is no water in the human body, adiuretin is released more and more.
The hypothalamus contains sensors that detect and relay the osmotic concentration. Blood pressure also plays an important role in regulating the amount of ADH secreted - the corresponding sensors are located in large blood vessels.
The most important function of ADH is the regulation of the water balance. The hormone causes via receptors on the collecting tubes of the kidneys, that water is led back into the body. This increases the concentration of urine while its amount decreases. In healthy people, this process is especially at night, because the sleep without urination is easily possible.
Adiuretin fulfills even more tasks. So it causes in larger quantities a narrowing of the blood vessels, whereby an increase in blood pressure is effected. In the liver, the hormone causes the release of sugar into other organs (glycolysis). This need exists with an increased energy requirement of the body, in which the sugar from the diet is not sufficient to supply the cells optimally.
A portion of adiuretin is not put on its way into the blood stream, but migrates into the pituitary frontal lobes. There it causes the secretion of ACTH (adrenocorticotropin). This peptide hormone in the adrenals causes the release of endogenous cortisol (glucocorticoids) and is thus responsible for the release of insulin. Since ADH is at the beginning of this chain, it is therefore also part of the hormonal stress mechanism.
Disturbances in the production of ADH can manifest as both overproduction and underproduction, with the latter occurring much more frequently. In diabetes insipidus centralis the organism has too little ADH. The reasons are many. Lack of or too low production of adiuretin or lack of transport to the posterior pituitary gland may be as responsible as inadequate storage in the hypothalamus or lack of transport to body cells. The consequences are the same in all cases, since no or too little ADH arrives at the destination in order to unfold its effect.
The main symptoms consist of increased urine output and severe thirst. Those affected lose urine without drinking much. Additional symptoms may include dry skin, difficulty sleeping, irritability or constipation. The disease can be diagnosed by laboratory tests, in particular by the thirst test: The patient is examined after a few hours without liquid intake laboratory. In a healthy person, due to the thinning, there is an increase in ADH, which can not be recorded in a patient.
A rare disorder related to adiuretine is overproduction of the hormone - Schwartz-Bartter syndrome. There is an excess of water in the organism, which increases the number of people affected. In addition, the blood is diluted so that symptoms occur due to the low concentration of sodium. Drowsiness, headaches or a sense of being apart are the consequences. The dilution of the blood is often determined by routine examination. In addition, a urine test can detect an excessive concentration of urine.
In both cases, the causes are extremely diverse. Often these are benign or malignant tumors of the hypothalamus, cerebral hemorrhage after accidents, vascular inflammation, a cyst or, more rarely, granulomatosis. In most cases, the disease can be treated well by eliminating the underlying problem.Tags: