vasopressyna

Vasopressyna, also known as vasopressin or antidiuretic hormone (ADH), is a nonapeptide hormone produced by magnocellular neurons in the hypothalamus and released from the posterior pituitary. It is synthesized as part of a larger precursor, preprovasopressin, and stored with the carrier protein neurophysin II. Secretion is primarily triggered by increases in plasma osmolality or decreases in blood volume, and it is released into the bloodstream from the posterior pituitary.

Vasopressyna exerts its effects through different receptors. V1a receptors on vascular smooth muscle mediate vasoconstriction, contributing to blood pressure regulation. V2 receptors on renal collecting ducts promote water reabsorption by increasing the insertion of aquaporin-2 channels into the apical membrane, concentrating urine. V1b receptors, primarily in the pituitary, influence the release of adrenocorticotropic hormone (ACTH) during stress. The combined actions help maintain fluid balance, osmolality, and circulatory stability.

Physiologically, vasopressyna plays a central role in maintaining body water homeostasis and blood pressure. It also participates in stress responses and, in some species, influences social and affiliative behaviors. Its dysregulation is clinically significant: excess vasopressin can lead to hyponatremia (syndrome of inappropriate antidiuretic hormone secretion, SIADH), while deficiency causes central diabetes insipidus, characterized by polyuria and polydipsia.

clinically, synthetic analogs are used therapeutically. Desmopressin (a selective V2 receptor agonist) treats certain bleeding disorders and von Willebrand disease, while vasopressin itself or terlipressin (a longer-acting analog) is used as a vasopressor in vasodilatory shock and in the management of esophageal variceal bleeding in some settings. Side effects include hyponatremia, fluid retention, and ischemic risks.

Vasopressyna has a long-standing history in physiology and medicine, underpinning essential mechanisms of fluid balance and hemodynamic regulation.