Somatostatin: a potent inhibitor of ACTH-hypersecretion in adrenal insufficiency.

Somatostatin (250 mug as a bolus i.v. and 250 mug as a 1-hr infusion) was administered to 5 patients with adrenal insufficiency of different origin. In each patient a sustained, progressive fall in plasma ACTH was observed during the infusion period. The mean maximal reduction in plasma ACTH was 43.8 +/- 5.9%. After cessation of the somatostatin infusion there was a rise of plasma ACTH to starting levels within 1/2 hour. These findings suggest that somatostatin is a potent inhibitor of ACTH secretion, however, only in a condition in which glucocorticoids are lacking.