The α-Adrenoceptor Control of Adrenocorticotropin Secretion in Man

Abstract

Oral administration to 6 normal male volunteers of an .alpha.-adrenoceptor agonist, guanfacine (4 mg daily for 4 days) had no significant effect on ACTH release induced by metyrapone (a single oral 1 g dose). The same treatment with guanfacine significantly reduced ACTH secretion stimulated by insulin-induced hypoglycemia in another group of 6 male volunteers. In man, the adrenergic system apparently has an inhibitory input on stress-induced ACTH secretion via .alpha.-adrenoceptors. The concept of .alpha.-adrenergic control of ACTH secretion in man is in agreement with some experimental in vivo and in vitro data recorded in animals.