Resistance of rat kidney mitochondrial membranes to oxidation induced by acute iron overload

The effect of iron-overload on rat kidney was studied after a single injection of iron-dextran. Total iron content in kidney and isolated kidney mitochondria was markedly elevated over control values. To assess mitochondrial damage by iron overload, succinate-cytochrome c reductase and NADH-cytochrome c reductase activities as well as the rate of succinate-dependent hydrogen peroxide generation were measured. None of these activities were significantly affected by acute iron overload. The net content and the rate of TBARS (thiobarbituric acid reactive species) formation in kidney homogenates from iron-treated rats was significantly higher than that of control animals. Total superoxide dismutase activity in the homogenates from iron overloaded kidney was decreased by 26%, as compared to controls. Catalase, glutathione peroxidase, and Mn-superoxide dismutase activities were not affected by the treatment. The content of alpha-tocopherol was consistently decreased in whole kidney homogenates (-31%), mitochondria from kidney medulla (-31%) and cortex (-34%), from iron-overloaded rats. Our data suggest that iron dextran treatment does not affect kidney integrity, even though increases in lipid peroxidation occur. Vitamin E appears to be effective in controlling iron-dextran dependent radical generation in kidney.