Regulatory Role of ACTH on Aldosterone in Aldosterone-Producing Adenoma

Abstract

Primary aldosteronism (PA), one of the most frequent causes of secondary hypertension, is mainly composed of two major subtypes: aldosteroneproducing adenoma (APA) and bilateral hyperaldosteronism (BHA). In APA, ACTH plays a dominant role in the regulation of circulating aldosterone level, while in physiological condition and BHA angiotensin II has a stronger effect. This pronounced regulation of aldosterone by ACTH in APA causes a differential response of aldosterone to either ACTH stimulation or ACTH suppression in APA from that in physiological condition and BHA, and therefore, ACTH stimulation test can be informative in differentiating APA among patients with PA and essential hypertension. Histologic studies have suggested a possibility that the origin of APA especially consisting of clear, lipid rich cells could be zona fasticulata, rather than zona glomerulosa. Recent studies have been focusing on molecular classification among APA, which could lead to a better understanding of ACTH responsiveness in APA.