Adrenal cortex — A newly recognized peripheral site of action of enkephalins

Abstract

Summary Two naturally occuring enkephalins, Leu- and Met-enkephalin, were shown to inhibit adrenal corticosteroid biosynthesis. In isolated rat adrenal cell system corticosterone, desoxycorticosterone and aldosterone, and in isolated bovine adrenal cells cortisol, corticosterone and aldosterone production were markedly depressed in a dose-dependent fashion, both under basal conditions and following stimulation with ACTH 1–24 . The inhibitory action of enkephalins on corticosteroid synthesis could be augmented by increasing the Ca 2+ -concentration in the cell-containing medium. The demonstration that opioid peptides interfere with corticosteroidogenesis directly at the adrenal level points to the existence of a peripheral neuroendocrine relationship.