Vasopressin receptor-adenylate cyclase interactions. Studies in an intact cultured renal epithelial cell line (LLC-PK1).

The antidiuretic action of vasopressin is mediated by activation of adenylate cyclase and generation of cyclic AMP. Radioligand binding and radiation inactivation studies have been done using a pig kidney epithelial cell line in culture to define the sequence of subunit interactions involved in the activation of adenylate cyclase by vasopressin. Based on the results of these studies and the known biochemical properties of the individual adenylate cyclase subunits, a hormonal activation model is proposed. According to this model, activation results from the sequential steps of dissociation of the alpha beta subunits of the guanyl nucleotide regulatory unit followed by the binding of GTP to dissociated alpha. The development of this model would not have been possible without the availability of the intact cultured cell system.