A synthetic peptide that is identical to the 24-amino acid segment at the N-terminal of adrenocorticotropic hormone. ACTH (1-24), a segment similar in all species, contains the biological activity that stimulates production of corticosteroids in the adrenal cortex. (en)
Cosyntropin combines with a specific receptor in the adrenal cell plasma membrane and, in patients with normal adrenocortical function, stimulates the initial reaction involved in the synthesis of adrenal steroids (including cortisol, cortisone, weak androgenic substances, and a limited quantity of aldosterone) from cholesterol by increasing the quantity of the substrate within the mitochondria. Cosyntropin does not significantly increase plasma cortisol concentration in patients with primary or secondary adrenocortical insufficiency. (en)