Adrenal steroid responses to ACTH in glucocorticoid-suppressible aldosteronism

To investigate adrenal responses to adrenocorticotrophin (ACTH), we infused graded doses of ACTH (1.25 to 20.0 mIU/30 minutes) in normal subjects, patients with low-renin essential hypertension (LREH), primary aldosteronism (PA), and glucocorticoid-suppressible hyperaldosteronism (GSH). Plasma aldosterone, cortisol, corticosterone, and 18-hydroxycorticosterone were measured. The results revealed a greater increase in the plasma aldosterone and 18-hydroxycorticosterone levels evoked by ACTH in the GSH group than in any other group, which suggested enhanced responsiveness of the aldosterone-producing cells to ACTH and a probable adrenal abnormality.