Role of pro-opiomelanocortin-derived peptides in the regulation of steroid production by human fetal adrenal cells in culture.

Synthetic (1-39)ACTH, (1-24)ACTH, (18-39)ACTH, alpha-MSH, met-enkephalin and alpha-, beta- and gamma-endorphin were tested for their ability to stimulate steroidogenesis by human fetal adrenal cells in culture. Adrenal cells were incubated with peptide hormones for two periods of 24h. On the third day of the experiment the cells were incubated with progesterone (4 micrograms/2 ml) for 8 h. At the doses tested only (1-39)ACTH, (1-24)ACTH and alpha-MSH stimulated steroidogenesis. None of the other peptides had any corticotrophic effect on the formation of cortisol, corticosterone or dehydroepiandrosterone sulphate (DHAS). At the highest doses tested, alpha-MSH (100 micrograms/2 ml) had a corticotrophic effect that was not different from that obtained with 20 ng (1-39)ACTH or (1-24)ACTH. At the lower doses (0.2-2 micrograms/2 ml), alpha-MSH stimulated the formation of DHAS (P less than 0.01) without stimulating the formation of cortisol.