Synthetic (1–39)ACTH, (1–24)ACTH, (18–39)ACTH, α-MSH, met-enkephalin and α-, βand γ-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 24 h. On the third day of the experiment the cells were incubated with progesterone (4 μg/2 ml) for 8 h. At the doses tested only (1–39)ACTH, (1–24)ACTH and α-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, α-MSH (100 μg/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 μg/2 ml), α-MSH stimulated the formation of DHAS (P<0·01) without stimulating the formation of cortisol.
Editorial: The Role of Peptide Hormones in Insect Physiology, Biochemistry, and Molecular Biology Processes