AJP - Renal Physiology, Vol 264, Issue 6 981-F988, Copyright © 1993 by American Physiological Society
Renal renin, angiotensinogen, and ANG I-converting-enzyme gene expression: influence of dietary protein
M. Martinez-Maldonado, J. E. Benabe, J. N. Wilcox, S. Wang and C. Luo
Department of Medicine, Atlanta Veterans Affairs Medical Center, Decatur 30033.
Low-protein (LP) feeding (6%) of rats results in renal hemodynamic changes
that are abolished by converting enzyme and nonpeptide AT1 inhibitors,
suggesting a role for intrarenal angiotensin II (ANG II). Dietary protein
is a stimulus for the expression of renal renin mRNA in intact and
partially nephrectomized rats. In the present study, LP increased renal
renin immunoreactivity and renin mRNA as assessed by in situ hybridization
and Northern blot analysis; whole kidney expression of angiotensinogen mRNA
was unaltered. Whole kidney, cortical, and medullary ANG
I-converting-enzyme (ACE) mRNA was also increased in LP vs. normal protein.
The changes occurred despite a reduced protein synthetic rate (RNA-to-DNA
ratio) in the kidney of LP, which did not change expression of renal
glyceraldehyde-3-phosphate dehydrogenase mRNA. These studies show for the
first time that LP diet increases the expression of renal renin and ACE
mRNA in intact rats; these may be responsible for the renal hemodynamic
changes of LP.
