Tissue-specific corticosteroidogenesis in the rat

The steroid aldosterone plays a major role in the maintenance of total body sodium homeostasis and also contributes to cardiovascular pathophysiology by mediating cardiac hypertrophy and fibrosis. In addition to classical adr enal production of aldosterone, endogenous tissue production of aldosterone has been observed in various organs; aldosterone biosynthesis in cardiac t issues, however, remains highly controversial. The current study provides a comprehensive evaluation of steroid hormone biosynthethic capabilities in multiple tissues from two distinct rat strains under unstimulated and stimu lated conditions. Panels of tissues from Wistar and Sprague-Dawley rats wer e probed for 11 beta-hydroxylase (P45011 beta) and aldosterone synthase (P4 50aldo) by reverse transcriptase-polymerase chain reaction (RT-PCR). Under unstimulated conditions, cardiac P45011 beta and P450aldo were detected onl y in Wistar rats. Angiotensin 11 (100 mu g/day) stimulated myocardial expre ssion of both enzymes in both strains. Cerebral cortex and mesenteric arter y message levels in both strains was reduced by angiotensin II. These data demonstrate the potential for local steroid synthesis in vascular, cardiac, renal, and neuronal tissues, and that biosynthesis of non-adrenal aldoster one may be differentially regulated between strains. This variability may t hus resolve in part or whole the current controversy over the existence of non-adrenal steroidogenic systems. (C) 2000 Elsevier Science Ireland Ltd. A ll rights reserved.