ACTH, also known as corticotropin, is a hormone secreted by the anterior pituitary gland that enhances the production of adrenal androgens. It is secreted in response to corticotropin-releasing factor from the hypothalamus. ACTH is a polypeptide made up of 39 amino acids that acts on the adrenal cortex, stimulating the synthesis and release of glucocorticoids and maintaining the integrity of the adrenal cortex. It also has non-adrenal actions such as mobilizing fat from tissues and stimulating melanocytes in the skin.