The influences of selenium deficiency (Se-D), chronic training, and an acute bout of exercise on hepatic and skeletal muscle antioxidant enzymes, i.e., Superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX), as well as glutathione S-transferase (GST) and tissue lipid peroxidation, were investigated in post-weaning male SpragueDawley rats. Se-D per se depleted GPX in both liver and skeletal muscle but had no effect on SOD or catalase activity. One hour of treadmill running (20 m/min, 0% grade and 27 m/min, 15% grade for untrained and trained rats, respectively) significantly elevated hepatic catalase and cytosolic SOD activity; more prominent activations were found in the Se-D or untrained rats, whereas skeletal muscle antioxidant enzymes were little affected. Ten weeks of training (1 h/day, 5 days/week at 27 m/min, 15% grade) increased hepatic mitochondrial SOD by 23% (P < 0.05) in Se-D rats. Both hepatic mitochondrial and cytosolic GPX were decreased by training whereas GPX was increased twofold in skeletal muscle mitochondria. Se-independent GPX was elevated by training only in the skeletal muscle mitochondria of Se-D rats. Lipid peroxidation (malondialdehyde formation) was increased by an acute bout of exercise in hepatic mitochondria of the untrained rats and in skeletal muscle mitochondria of the Se-D rats. These data indicate that antioxidant enzymes in liver and skeletal muscle are capable of adapting to selenium deficiency and exercise to minimize oxidative injury caused by free radicals.
Bibliographical noteFunding Information:
i The present investigation was supported Grant AM 10334 from the National Institutes Health, and by the Vilas Trust of the University Wisconsin-Madison. s To whom correspondence should be addressed. s Abbreviations used: ALT, alanine aminotransferase; CS, citrate synthase; GPX, glutathione peroxidase; GST, glutathione S-transferase; HsOs, hydrogen peroxide; . OH, hydroxyl radical; MDH, malate dehydrogenase; MDA, malondialdehyde; GSSG, oxidized glutathione; GSH, reduced glutathione; Op, superoxide anion; SOD, superoxide dismutase.
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