Calcium efflux and steroid output from superfused rat adrenal cells: effects of potassium, adrenocorticotropic hormone,

1. The efflux of 45Ca from prelabelled dispersed rat adrenal capsular and decapsulated cell preparations was studied with a column superfusion system. Corticosterone and aldosterone outputs were measured by direct and extraction radioimmunoassay s. 2. The stimulants potassium, adrenocorticotropic hormone (ACTH), serotonin and adenosine 3': 5'-cyclic monophosphate (cyclic AMP), at concentrations which gave marked increases in steroid output, had no significant effect on the rate of 45Ca efflux from capsular cell preparations (mainly zona glomerulosa). 3. ACTH, at a concentration which stimulated steriodogenesis similarly, did not alter the rate of 45Ca efflux from decapsulated cell preparations (zona fasciculata/reticularis). 4. [Asp',ValS]Angiotensin I1 caused dosedependent increases in the rate of 45Ca efflux from capsular cells which correlated with corresponding increases in steroid output, but had no effect either on 45Ca efflux or corticosterone output in decapsulated cell preparations. [desAspl,IleS]Angiotensin I1 (angiotensin 111)