Responses of isolated guinea-pig adrenal cells to ACTH and pro-opiocortin-derived peptides.

A comparison of the responses of isolated guinea-pig adrenal cells to ACTH and pro-opiocortin-derived peptides was carried out by measuring cortisol, aldosterone, androstenedione and dehydroepiandrosterone production. With concentrations below 10,000 pg/ml, no steroidogenic activity was found in response to either beta-LPH, gamma-LPH, gamma 3-MSH or the 16K fragment, whether assayed alone or in association with ACTH. At concentrations above 10,000 pg/ml, gamma-LPH (100 ng), the 16K fragment (100 ng) and beta-endorphin (500 ng) proved to be totally inactive. beta-LPH from 25 to 250 ng, however, exhibited a significant though slight stimulatory effect on cortisol, aldosterone and androstenedione production. Its effectiveness on aldosterone production was especially marked, but the extent of the response was modest in view of the concentrations used.