Captopril Test

This is an ACE inhibitor (see physiology section) blocking angiotensin II production from angiotensin I, thereby normally inhibiting aldosterone release from the adrenal cortex.. When given to patients with aldosterone-producing adenomas, plasma aldosterone levels remain unchanged (due to the tumour being responsive only to ACTH). When given to patients with idiopathic hyperaldosteronism, plasma aldosterone levels will fall as the hyperplastic glands are responsive to angiotensin II.