There was a remarkable reduction in the levels of CuZn superoxide dismutase (SOD) and Mn SOD (key enzymes involved in the regulation of superoxide radicals), but an increased level of gp91phox (a subunit of NADPH oxidase involved in the production of superoxide anion), in the kidneys of rats with chronic renal failure (5/6 nephrectomized) [45]. This evidence concerns the gene SOD1 and chronic kidney disease.