AVPR2 is a protein that acts as receptor for arginine vasopressin. AVPR2 belongs to the subfamily of G-protein coupled receptors. Its activity is mediated by the Gs type of G proteins, which stimulate adenylate cyclase. AVPR2 is expressed in the kidney tubule, predominantly in the distal convoluted tubule and collecting ducts, in fetal lung tissue and lung cancer, the last two being associated with alternative splicing. AVPR2 is also expressed outside the kidney and when stimulated a variety of clotting factors are released into the bloodstream. In the kidney AVPR2's primary property is to respond to arginine vasopressin by stimulating mechanisms that concentrate the urine and maintain water homeostasis in the organism. When the function of AVPR2 is lost, the disease Nephrogenic Diabetes Insipidus (NDI) results.