VASOPRESSIN RESISTANCE IN CHRONIC-RENAL-FAILURE - EVIDENCE FOR THE ROLE OF DECREASED V-2 RECEPTOR MESSENGER-RNA

Studies were performed to determine the mechanism underlying deficient arginine vasopressin (AVP)-stimulated adenylyl cyclase activity in chronic renal failure (CRF). As compared to control, principal cells cultured from the inner medullary collecting tubule of rats previously made uremic by 5/6 nephrectomy fail to accumulate cAMP when stimulated with AVP. CRF cells do respond normally to forskolin or cholera toxin and the defect in AVP responsiveness is not prevented by treatment with pertussis toxin, by cyclooxygenase inhibition, or by inhibition or down-regulation of protein kinase C. In contrast to their lack of responsiveness to AVP, CRF cells respond normally to other agonists of adenylyl cyclase such as isoproterenol or prostaglandin E(2). Plasma membranes prepared from the inner medullae of CRF rats exhibit a marked decrease in apparent AVP receptor number but no change in the apparent number of beta adrenergic receptors. Reverse transcriptase PCR of total RNA from the inner medullae of CRF animals reveals virtual absence of V-2 receptor mRNA; mRNA for alpha(s) is present in normal abundance. These studies indicate that AVP resistance in CRF is due, at least in part, to selective down-regulation of the V-2 receptor as a consequence of decreased V-2 receptor mRNA.