vasopressiini

Vasopressiini, also known as antidiuretic hormone (ADH) or arginine vasopressin (AVP), is a peptide hormone produced by the hypothalamus and released by the posterior pituitary gland. Its primary function is to regulate water balance in the body. Vasopressiini acts on the kidneys, specifically on the collecting ducts and distal tubules, increasing their permeability to water. This increased permeability allows more water to be reabsorbed from the filtrate back into the bloodstream, thereby reducing the volume of urine produced and concentrating the urine.

The release of vasopressiini is stimulated by increased osmolarity of the blood, which is detected by osmoreceptors in the hypothalamus. Dehydration, for example, leads to a higher concentration of solutes in the blood, triggering vasopressiini secretion. Conversely, a decrease in blood osmolarity, such as after drinking a large volume of water, suppresses vasopressiini release, leading to increased urine output. Vasopressiini also plays a role in blood pressure regulation by causing vasoconstriction of blood vessels, which increases peripheral resistance and thus raises blood pressure. This effect is more pronounced at higher concentrations of the hormone. Disorders related to vasopressiini can lead to conditions such as diabetes insipidus, characterized by excessive thirst and urination due to insufficient vasopressiini production or kidney response.