Vasopressin receptor V_1a polyclonal antibody

Arginine vasopressin (AVP) is a nonapeptide hormone produced in magnocellular neurons of the hypothalamus, which functions as an antidiuretic in the kidney and systemically as a regulator of vasoconstriction, blood volume, and blood pressure. AVP acts by binding to a set of specific seven-transmembrane domain-containing G-protein coupled receptors (GPCR) classified into three groups: V1a (V1) receptors regulate vasoconstriction, and are expressed in vascular smooth muscle, kidney, myometrium, bladder, adipocytes, hepatocytes, platelets and testis; V1b (V3) receptors stimulate adrenocorticotropic hormone (ACTH) release in the anterior pituitary, but may also participate in corticotropin-releasing hormone (CRH) release by the hypothalamus; and V2 receptors of the kidney regulate the antidiuretic effects of AVP. The V1b receptor signals through coupling of Gq/11 alpha subunits, activating phospholipase C and release of intracellular Ca2+ via phosphoinositide second messengers. V1b receptor overexpression is a common marker for ACTH-secreting corticotropic adenomas.