PRESENCE OF RENIN WITHIN INTRAMITOCHONDRIAL DENSE BODIES OF THE RAT ADRENAL-CORTEX

Presence of renin within intramitochondrial dense bodies of the rat ad renal cortex. Am. J. Physiol. 271 (Endocrinol. Metab. 34): E439-E450, 1996.-It has been suggested that tissue-specific expression of the gen es of the renin-angiotensin system (RAS) leads to local generation of angiotensin (ANG) II with specific physiological implications. We demo nstrate here that an intracellular RAS exists in adrenal glomerulosa c ells; 60 h after bilateral nephrectomy and hemodialysis, renin and pro renin were eliminated from the circulation, whereas intraadrenal renin content increased (control rats: 2 +/- 0.5 ng ANG I . mg(-1). h(-1); anephric rats: 25 +/- 2). Thus renin is produced locally within adrena l cells. We obtained immunocytochemical and biochemical evidence for t he presence of renin within intramitochondrial dense bodies of the zon a glomerulosa. After nephrectomy, dense bodies increased in number, si ze, and renin content (control rats: 2.5 +/- 0.7 ng ANG I . mg(-1). h( -1); anephric rats: 43 +/- 7). Angiotensin-converting enzyme (ACE) was also present within mitochondria and their dense bodies. In addition, in adrenal cortex of anephric rats, giant dense bodies were observed, which contain renin and strongly react with an anti-angiotensinogen a ntibody. The localization of renin, ACE, and angiotensinogen at these sites provides new evidence for the existence of an intracellular adre nal RAS.