May contribute to arginine-vasopressin (AVP)-mediated regulation of renal salt-water balance, glucose and lipid metabolism, apoptosis, and/or cell cycle. Binds arginine-vasopressin but not angiotensin II and acts as an arginine-vasopressin V2 receptor. Plays a role in modulating inflammatory responses in the colon to allow recovery from intestinal epithelial damage and limit tumorigenic potential. Protects against the development of colitis by controlling the composition of the gut microbiota by preventing colonization of the colon by harmful, inflammation-inducing bacteria such as Prevotella species. May mediate activation of CASP1 via ASC, promote activation of NF-kappa-B and stimulate cAMP accumulation (By similarity).