Production of Renin, Angiotensin II, and Aldosterone by Adrenal Explant Cultures: Response to Potassium and Converting Enzyme Inhibition*

Abstract

The existence of renin in a number of extrarenal tissues has been well documented, but the physiological role of extrarenal renin remains unknown. To study the physiological role of adrenal renin, we developed a serum-free culture system for adrenal capsular/zona glomrulosa explants. Explants showed good viability in culture (greater than 80%), and demonstrated net production of aldosterone, angiotensin II, and prorenin. Aldosterone production was consistently stimulated by an increase in potassium (6 mM) in the culture medium. Both aldosterone and angiotensin II production could be attenuated by adding the angiotensin converting enzyme inhibitor lisinopril to the culture medium (0.1 mM). These data suggest that rat adrenal explants are capable of producing all of the components of a functional renin-angiotensin-aldosterone system and that these components can interact in response to physiological stimuli. These findings support the hypothesis that a local adrenal renin system may play a physiological role in the control of adrenal aldosterone production.