ANGIOTENSIN-INDUCED STEROIDOGENESIS IN RABBIT ADRENAL - EFFECTS OF PH AND CALCIUM

The effect of variations in pH and Ca2+ on angiotensin II (A-II)-induced steroidogenesis was tested on isolated adrenal glomerulosa cell suspensions. The results show that a reduction in pH from 7.4 to 6.5 produces both a shift to the left of the A-II dose-response curve as well as an increase in maximum steroid production. In contrast, removal of Ca2+ from the incubation medium virtually abolished steroidogenesis to A-II (5 × 10-9M), KC1 (10 mM) and ACTH (250 μU/ml). The Ca2+ antagonist D-600, however, was less effective than simple removal of Ca2+ as 10-4 M was required to block the steroidogenic response to these same agonists. The results indicate that the response characteristics of this system to A-II resemble most closely those seen with isolated arterial smooth muscle - especially rabbit aortic strips. © 1979.