Inhibitory effects on steroid production from isolated adrenal cells of rhesus monkey (Macaca mulatta) of pro-opiomelanocorticotrophic peptides.

Adrenal glands from Rhesus monkeys (Macaca mulatta) of 160 days gestation, newborn, 2 months-old infants or 6 months-old infants were excised and prepared, by a collagenase digestion, as a cell suspension. The cells were incubated with 10 pg/ml, 100 pg/ml or 1 ng/ml of a peptide of the ACTH/pro-opiomelanocortin 'family', 57K, 31K, 20K, alpha MSH, ovine-CLIP or gamma LPH either in the presence or absence of 166 pg/ml ACTH1-39. The production by cortisol and androstenedione was measured by radioimmunoassay. Using the steroid production by aliquots of the cell suspension with either no stimulating agent or ACTH1-39 alone as controls, the net influence of these different peptides on basal or ACTH1-39-stimulated production was observed. alpha MSH, ovine-CLIP and gamma LPH had no influence on either basal or stimulated cortisol or androstenedione production. Corticotrophic peptides of 57K, and 20K and pro-opiomelanocortin each had a steroidogenic activity alone, in all age groups. In the fetal and newborn monkeys' adrenal cells, peptides of 57K and 20K at 1 ng/ml had an inhibitory influence on ACTH1-39 stimulated cortisol and androstenedione production. The influence of the 20K peptide is partially inhibitory as the steroidogenic potential of this peptide is not additive with that of ACTH1-39. These results show that, as observed in other species, that the ACTH/pro-opiomelanocortin range of peptides are inhibitory to the action of ACTH1-39 in the developing adrenal.