Differential regulation of rat glomerular and proximal tubular
renin mrna following uninephrectomy.
Tank, Julia E., Orson W. Moe, Robert A. Star, and William L. Henrich.
Departments of Medicine, DALLAS VA MEDICAL CENTER and the
UNIVERSITY OF TEXAS SOUTHWESTERN MEDICAL CENTER, DALLAS, TX 75235
APStracts 2:0200F, 1995.
Angiotensin II is thought to play a 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 on circulating,
juxtaglomerular, glomerular and proximal tubular (PT) renin. PRA was
unchanged 2 weeks following uninephrectomy, and fell slightly at 6
weeks. Single kidney renin secretory capacity and cortical renin
mRNA, reflecting juxtaglomerular renin, were unchanged at 2 and 6
weeks. Using quantitative competitive RT-PCR, renin mRNA in
microdissected glomeruli and PT was dramatically increased 2 weeks
post-uninephrectomy (glomeruli: sham 1.2+/-0.3 vs UNX 8.8+/-1.9x105
copies/glom; PT: sham 4.6+/-0.9 vs UNX 17.7+/-5.1x103 copies/mm). By
6 weeks, glomerular renin was unchanged and PT renin mRNA was
markedly suppressed (glomeruli: sham 2.9+/-1.2 vs UNX 4.2+/-1.1x105
copies/glom; PT: sham 7.5+/-2.1 vs UNX 1.0+/-0.3x103 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 II, and thereby affect renal structural and functional
adaptations following uninephrectomy.
Received 1 June 1995; accepted in final form 6 November 1995.
APS Manuscript Number F176-5.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 November 95