Effects of pro-opiomelanocortin peptides on adrenocortical steroidogenesis.

Whilst studying the effects of pro-opiomelanocortin (POMC) peptides on adrenocortical steroidogenesis we showed that alpha-melanocyte-stimulating hormone (alpha-MSH) has a specific glomerulotropic effect and potentiates both the mineralocorticotropic and glucocorticotropic effects of ACTH. The fragments ACTH-(4-10) and ACTH-(11-13) are responsible for the glomerulotropic effect of alpha-MSH. beta-Endorphin enhances, inhibits or has no effect on corticosteroidogenesis, depending on the dose and on the functional state of the adrenocortical cells (saturation of the receptors). beta-Endorphin antagonizes the effect of alpha-MSH on aldosterone production. It is suggested that the modulatory effects of POMC peptides on adrenocortical steroidogenesis may be of physiological significance.