The primary action of corticotropin

The primary action of corticotropin (adrenocorticotropin; ACTH) on the adrenal cortex is to increase cortisol secretion by increasing its synthesis; intraadrenal cortisol storage is minimal [1]. The major adrenal steroid hormones are synthesized in different areas of the adrenal cortex: glucocorticoids (particularly cortisol), androgens, and estrogens in the zona fasciculata and reticularis; and aldosterone in the zona glomerulosa. An appreciation of these pathways serves as the basis for understanding the different forms of congenital adrenal hyperplasia (CAH) and isolated hypoaldosteronism in which there are defects in the function of the enzymes involved in adrenal steroid hormone synthesis. It is also critical for understanding the mechanisms of action of new drugs directed at reducing cortisol synthesis in patients with Cushing's syndrome