Hydrogen peroxide metabolism and oxidative stress in cortical, medullary and papillary zones of rat kidney.
The cortical, medullary and papillary regions of rat kidney were evaluated for a series of parameters related to hydrogen peroxide metabolism and oxidative stress. The rates of oxygen uptake, prostaglandin synthesis and malondialdehyde production by kidney slices were: 47, 0.003 and 0.051 mumol/h g wet wt., respectively, in cortex, 32, 0.023 and 0.035 in medulla and 22, 0.034 and 0.007 in papilla. The activities of superoxide dismutase, catalase and glutathione peroxidase were: 144 +/- 16 U/g wet wt., 880 +/- 100 pmol/g wet wt. and 177 +/- 16 U/g wet wt. in cortex; 97 +/- 9 U/g wet wt., 550 +/- 50 pmol/g wet wt. and 142 +/- 18 U/g wet wt. in medulla; and 23 +/- 2 U/g wet wt., 90 +/- 9 pmol/g wet wt. and 147 +/- 5 U/g wet wt. in papilla. Hydrogen peroxide steady-state concentrations were 0.09 +/- 0.01, 0.07 +/- 0.01 and 0.08 +/- 0.01 microM whereas alpha-tocopherol content was 21 +/- 2, 23 +/- 1 and 34 +/- 3 mumol/g wet wt. and hydroperoxide-initiated chemiluminescence was 22 +/- 2, 33 +/- 2 and 14 +/- 1 cpm. 10(-3)/mg prot for cortex, medulla and papilla, respectively. After 60 min ischemia-30 min reperfusion hydroperoxide-initiated chemiluminescence and hydrogen peroxide steady-state concentration increased by 30% and 60% in cortex and 80% and 60% in medulla, whereas alpha-tocopherol content decreased by 30%, 50% and 2% in cortex, medulla and papilla, respectively. The reperfusion/control ratio of hydroperoxide-initiated chemiluminescence and hydrogen peroxide steady-state concentrations in cortex and medulla indicate the occurrence of oxidative stress after ischemia-reperfusion. The lower sensitivity to oxidative stress found in papilla could be explained by the relatively high relationship of alpha-tocopherol content to hydrogen peroxide production rate in this sub-organ.
Instituto de Quimica y Fisicoquimica Biologicas, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires, Argentina.
B
B
Gonzalez-Flecha
P
P
Evelson
N
N
Sterin-Speziale
A
A
Boveris
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007511:Ischemia / Q000378:metabolism; D007672:Kidney Cortex / Q000098:blood supply / Q000378:metabolism*; D007679:Kidney Medulla / Q000098:blood supply / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008315:Malondialdehyde / Q000032:analysis; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D011453:Prostaglandins / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism; D014810:Vitamin E / Q000032:analysis
D000975:Antioxidants; D011453:Prostaglandins; D014810:Vitamin E; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase