Aldosterone biosynthesis: Interrelationship of regulatory factors

Abstract

There are three well defined control mechanisms for aldosterone secretion: the renin-angiotensin system, potassium and adrenocorticotropin (ACTH). Although physiologic levels of ACTH under certain circumstances may stimulate aldosterone secretion, ACTH seems to be less important than potassium or the renin-angiotensin system. In normal man the renin-angiotensin system and potassium regulate aldosterone secretion through negative feedback loops. Under ordinary circumstances both systems are probably of equal importance, with the level of aldosterone secreted determined by the integration of signals from each loop. Furthermore, either dietary sodium or potassium can sensitize the aldosterone secretory response to various acute stimuli. This interrelationship between potassium and the reninangiotensin system can be altered under special circumstances with either assuming dominant control of aldosterone secretion. For example, in norman man when volume, dietary sodium and/ or posture are altered changes in aldosterone secretion correlate best with changes in the renin-angiotensin system. On the other hand, in anephric man and in patients with primary aldosteronism, potassium appears to be the dominant factor regulating aldosterone secretion.