- Abbreviation for adrenocorticotropic hormone.- big A. a form of A., produced by certain tumors, which is a larger and more acidic peptide molecule than little A., but is not immunochemically distinguishable from it and does not exert any of the biologic effects characteristic of A.; proteolytic digestion of big A. yields hormonally active little A CTH.* * *adrenocorticotropic hormone
* * *ACTH .ā-.sē-(.)tē-'āch n a protein hormone of the anterior lobe of the pituitary gland that stimulates the adrenal cortex called also adrenocorticotropic hormone
* * *a hormone synthesized and stored in the anterior pituitary gland, large amounts of which are released in response to any form of stress. Its release is stimulated by corticotrophin-releasing hormone. ACTH controls the secretion of corticosteroid hormones from the adrenal gland. An analogue of ACTH, tetracosactide, is administered by injection to test adrenal function (see short Synacthen test).
* * *adrenocorticotropic hormone; see corticotropin.
Medical dictionary. 2011.