Antioxidant-oxidant balance in the glomerulus and proximal tubule of the rat kidney.
1. Antioxidant and oxidative enzymes were examined in renal glomeruli and proximal tubules of healthy young rats (10-12 weeks old), and results were related to the superoxide anion generation of these tissues. 2. Activities of superoxide dismutases, catalase, and glutathione peroxidase were 3- to 6-fold higher in proximal tubules than in glomeruli. Similarly, enzyme levels and mRNA levels of superoxide dismutases and catalase were significantly higher in proximal tubules. 3. NADH- and NADPH-dependent oxidase activity and xanthine oxidase activity were not different in glomeruli and proximal tubules. 4. Measurements with lucigenin-enhanced chemiluminescence in vital tissues indicated 10-fold higher rates of superoxide anion in glomeruli than in tubules. 5. Compared with the young rats, tubules of 8-month-old rats had significantly higher superoxide anion rates and lower superoxide dismutase activity, whereas NADH- and NADPH-dependent oxidase activities were unchanged. 6. We conclude that considerable differences in the antioxidant-oxidant balance exist between the glomerulus and proximal tubule. Results from experiments using chemiluminescence in vital tissues suggest that changes in the antioxidant-oxidant balance have an effect on oxygen radical levels. The relevance of the observed differences to glomerular and tubulo-interstitial disease remains to be determined, but a greater susceptibility of the glomerulus to oxidant stress might be anticipated.
Gwinner
W
W
Division of Nephrology, Department of Internal Medicine, Medical School Hannover, Germany.
Deters-Evers
U
U
Brandes
R P
RP
Kubat
B
B
Koch
K M
KM
Pape
M
M
Olbricht
C J
CJ
D000818:Animals; D002374:Catalase / Q000096:biosynthesis / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D006706:Homeostasis; D007678:Kidney Glomerulus / Q000201:enzymology / Q000502:physiology*; D007687:Kidney Tubules, Proximal / Q000201:enzymology / Q000502:physiology*; D008163:Luminescent Measurements; D008297:Male; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000096:biosynthesis / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D014158:Transcription, Genetic; D014969:Xanthine Oxidase / Q000378:metabolism
D012333:RNA, Messenger; D013481:Superoxides; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D014969:Xanthine Oxidase; D009247:NADH, NADPH Oxidoreductases