The mechanism of secretion of adrenal steroid hormones from adenomas of primary aldosteronism and Cushing's syndrome was studied in 10 patients with primary aldosteronism and in 3 patients with Cushing's syndrome in in vivo and in vitro experiments.
In all of the 10 patients with primary aldosteronism, ACTH stimulated aldosterone secretion from the adenomas more significantly than did angiotensin II and III. DOC and cortisol which were contained in the adenomas were also stimulated more significantly by ACTH than by angiotensin II and III.
Responses of the adenomas of Cushing's syndrome to various stimulations were less than those of primary aldosteronism. Secretion of cortisol and aldosterone from the adenomas of Cushing's syndrome was stimulated by ACTH and angiotensin II to a similar degree.
From these studies, it seems that secretion of adrenal steroid hormones from adenomas of primary aldosteronism is more sensitive to extraadrenal stimulations than that of Cushing's syndrome, and ACTH is the main factor in the control of the secretion of adrenal steroid hormones from the adenomas.