ACTH is an abbreviation of the chemical substance adrenocorticotropic hormone. This hormone is produced, stored, and released into the blood by the pituitary gland, a pea-sized organ that lies at the base of the brain. ACTH is necessary for the normal growth and function of the adrenal glands, two organs located on top of the kidneys. ACTH stimulates the adrenal glands to secrete various hormones, including a group called glucocorticoids. Glucocorticoids regulate the use of digested food and help the body adjust to stress.