Stimulation of aldosterone production by beta-melanotropin.

Experimental and clinical evidence suggests that a non-ACTH pituitary factor(s) is important in the regulation of aldosterone secretion in certain conditions. Earlier studies have suggested that beta-melanotrophin (beta-MSH) has only weak steroidogenic potency on the adrenal gland in the rat, but recently Challis et al.5 and Rudman et al.6 have reported that alpha- and beta-MSH have a trophic action on fetal adrenal gland. However, little is known about the effect of beta-MSH on aldosterone production. We recently reported that beta-lipotropin (beta-LPH) stimulates aldosterone production in rat capsular cells. As the amino acid sequence of beta-MSH is contained within the beta-LPH structure, we have now investigated the aldosterone-stimulating activity of synthetic beta-MSH. Our results indicate that beta-MSH causes a dose-dependent increase in aldosterone production in rat capsular cells which is blocked by a synthetic beta-MSH analogue. The synthetic hormone does not increase corticosterone production in decapsular cells.