The V2 receptor is expressed in the kidney tubule, predominantly in the distal convoluted tubule and collecting ducts, where its primary property is to respond to the pituitary hormone arginine vasopressin (AVP) by stimulating mechanisms that concentrate the urine and maintain water homeostasis in the organism. When the function of this gene is lost, the disease Nephrogenic Diabetes Insipidus (NDI) results. The V2 receptor is also expressed outside the kidney although its tissue localization is uncertain. When these ‘extrarenal receptors’ are stimulated by infusion of a V2 selective agonist (dDAVP), a variety of clotting factors are released into the bloodstream. The physiologic importance of this property is not known. The V2 receptor activates G(s) proteins which lead to the activation of adenylyl cyclase which produces the secondary messenger cAMP. cAMP activates PKA (protein kinase A) which phosphorylates downstream effectors that lead to a specific cellular response.

EXAMPLE: Vasopressin Regulation of Water Homeostasis References