vazopresszin

Vazopressin, 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 role is to regulate water balance in the body. Vazopressin acts on the kidneys, specifically on the collecting ducts and distal tubules, increasing their permeability to water. This allows the kidneys to reabsorb more water back into the bloodstream, thereby reducing urine output and concentrating the urine. This mechanism is crucial for preventing dehydration and maintaining proper blood osmolarity.

Beyond its role in water homeostasis, vazopressin also plays a part in vasoconstriction, a process where blood vessels narrow. This effect contributes to increasing blood pressure, which is particularly important during periods of low blood volume or pressure. Vazopressin is also involved in social behaviors, bonding, and maternal care in some species, though its precise roles in human social cognition are still being actively researched. Disruptions in vazopressin production or function can lead to conditions such as diabetes insipidus, characterized by excessive thirst and the production of large amounts of dilute urine, or Syndrome of Inappropriate Antidiuretic Hormone secretion (SIADH), which results in water retention and hyponatremia.