role in the renal adaptations to reduced renal mass, but earlier work has shown that plasma renin activity (PRA) does not increase in this setting. To examine this paradox, we studied the effect of uninephrectomy (UNX) on circulating, juxtaglomerular, glomerular, and proximal tubular (PT) renin. PRA was unchanged 2 wk following UNX and fell slightly at 6 wk. Single kidney renin secretory capacity and cortical renin mRNA, reflecting juxtaglomerular renin, were unchanged at 2 and 6 wk. With quantitative competitive reverse transcription-polymerase chain reaction, renin mRNA in microdissected glomeruli and PT were dramatically increased 2 wk post-UNX (for glomeruli: sham, 1.2 ± 0.3, vs. UNX, 8.8 ± 1.9 × 105 copies/glomerulus; for PT: sham, 4.6 ± 0.9, vs. UNX, 17.7 ± 5.1 × 103 copies/mm). By 6 wk, glomerular renin was unchanged, and PT renin mRNA was markedly suppressed (for glomeruli: sham, 2.9 ± 1.2, vs. UNX, 4.2 ± 1.1 × 105 copies/glomerulus; for PT: sham, 7.5 ± 2.1, vs. UNX, 1.0 ± 0.3 × 103 copies/mm). These results demonstrate differential regulation of the circulating, juxtaglomerular, glomerular, and PT renin systems. Early activation of glomerular and PT renin may result in increased local generation of angiotensin and thereby affect renal structural and functional adaptations following UNX. polymerase chain reaction; glomerulus; proximal tubule; kidney; angiotensin II.
ASJC Scopus subject areas
- Physiology (medical)