ACTH

The common abbreviation for adrenocorticotrophic hormone (also called corticotrophin). ACTH is produced by the anterior pituitary gland and stimulates the adrenal cortex (outer layer of the adrenal glands) to release various corticosteroid hormones, most importantly hydrocortisone (cortisol) but also aldosterone and androgen hormones. ACTH production is controlled by a feedback mechanism involving both the hypothalamus and the level of hydrocortisone in the blood. ACTH levels increase in response to stress, emotion, injury, infection, burns, surgery, and decreased blood pressure. A tumour of the pituitary gland can cause excessive ACTH production which leads to overproduction of hydrocortisone by the adrenal cortex, resulting in Cushing’s syndrome. Insufficient ACTH production results in decreased production of hydrocortisone, causing low blood pressure. Synthetic ACTH is occasionally given by injection to treat arthritis or allergy.