ALDOSTERONE PRODUCTION BY SHEEP ADRENAL-GLANDS INVITRO

A novel technique for the preparation of adrenal tissue from large animals (sheep) is presented. Multiple adrenal cortex biopsies are taken using a 2 mm diameter dermatological punch, and homogeneous pools of 10 tissue cylinders (1 from each gland) were incubated. Aldosterone, corticosterone and cortisol in the incubation medium were measured by double isotope derivative dilution assay. The mean within-incubation coefficient of variation of aldosterone production was 15.8%, while between days, unstimulated aldosterone production ranged from 0.02-0.25 .mu.g/100 mg tissue per 2 h. Aldosterone production was stimulated by ACTH, angiotensin II and K ions, in a manner similar, but at higher doses, to that reported for sheep in vivo. Serotonin (10-3 mol/l) inhibited aldosterone production, lower concentrations having no effect. Substrate levels of progesterone, DOC [deoxycorticosterone] and corticosterone (25 .mu.g/ml) stimulated aldosterone output, while cortisol inhibited aldosterone production. The incubation system described is simple, with a high degree of reproducibility, and has the advantage that up to 30 comparable incubation flasks can be prepared for any incubation, providing a simple technique for testing possible agonists or antagonists of steroid production.