PRINCIPAL CELL-SPECIFIC ANTIGEN AND HORMONAL REGULATORY NETWORK IN RC.SVTSA58 CELL-LINE

We used a dual immunomorphological and physiological approach to demon strate that the RC.SVtsA58 rabbit cortical cell line exhibits features of highly differentiated cortical collecting tubule (CCT) principal c ells (PC). First, we raised monoclonal antibodies against RC.SVtsA58 c ells and screened their reactivity with the rabbit kidney: three were specific for the basolateral domain of CCT PC and bound to 100% of RC. SVtsA58 cells. Second, we showed that bradykinin, atrial natriuretic p eptide, and prostaglandin E(2) increased intracellular Ca2+, guanosine 3',5'-cyclic monophosphate, and adenosine 3',5'-cyclic monophosphate (cAMP), respectively. In addition, 10 nM bradykinin inhibited desmopre ssin-elicited cAMP production by greater than or equal to 40%; this ef fect was suppressed by 10 mu M Ofindomethacin and was reproduced with 1 nM of prostaglandin E(2), indicating the conservation of arginine va sopressin-related regulatory loops described in microdissected CCT and freshly isolated cells. However, RC.SVtsA58 cells also express interc alated cell markers even after repeated cloning, which suggests that t sA58, a temperature-sensitive strain of simian virus-40, has transform ed a multipotent type of PC in keeping with the cell interconversion h ypothesis.