ANGIOTENSIN-II STIMULATES GROWTH AND STEROIDOGENESIS IN ZONA-FASCICULATA-RETICULARIS CELLS FROM BOVINE ADRENAL-CORTEX VIA THE AT1 RECEPTOR SUBTYPE

Primary cultures of bovine adrenocortical zona fasciculata/reticularis (zfr) cells responded to angiotensin II (AII) with a dose-dependent i ncrease in [H-3]thymidine incorporation into DNA. The effect was maxim al at 100 nmol/liter AII, and was dose dependently inhibited by (sar1, ala8)-AII (saralasin) and DuP753, but not by PD123177. Both All-stimul ated cortisol secretion and phosphoinositidase C activity were also in hibited by saralasin and DuP753, but not by PD123177. Pharmacological analysis of the antagonism of AII-stimulated cortisol secretion by sar alasin and DuP753 produced pA2 values of 8.79 and 7.02, respectively. Whereas the pA2 for saralasin agreed closely with previous measurement s in other systems, DuP753 was at least one order of magnitude less po tent in inhibiting the action of AII in bovine zfr cells compared to p revious measurements in rabbit vascular smooth muscle. We conclude tha t the steroidogenic and mitogenic effects of AII in bovine zfr cells a re mediated by the AT1 receptor.