ACTH


ACTH
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.
- little A. a term coined to denote the conventional A. molecule when contrasted with big A..
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adrenocorticotropic hormone

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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

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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).

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adrenocorticotropic hormone; see corticotropin.

Medical dictionary. 2011.