RESPONSES OF ANTIOXIDANT SYSTEM TO ACUTE AND TRAINED EXERCISE IN RAT-HEART SUBCELLULAR-FRACTIONS

The effects of acute and trained exercise on antioxidant enzymes (AGE) , glutathione (GSH), and malondialdehyde (MDA) were compared in rat he art subcellular fractions and red blood cells. Fischer-344 rats were e xercised acutely to 100% VO2 max and another group of Fischer-344 rats were given trained exercise for 10 weeks. The AOE and MDA were measur ed by spectrophotometry and GSH and oxidized GSH (GSSG) by high pressu re liquid chromatography. Trained exercise significantly increased cyt osol GSH to 131% of sedentary control (SC). Acute exercise significant ly increased mitochondrial superoxide dismutase, catalase, and glutath ione peroxidase by 167%, 358%, and 129% of SC, respectively, whereas e nzyme activities following trained exercise were increased by 133%, 16 6%, and 128% of SC. The mitochondria/cytosolic ratio for superoxide di smutase, catalase, and glutathione peroxidase after acute exercise inc reased to 1.9, 2.7, and 1.7, respectively, whereas the respective rati os of these enzymes after trained exercise were 1.3, 1.6, and 1.3. Acu te exercise contributed to oxidative stress more than trained exercise . Acute exercise resulted in a larger increase in enzyme activities th an trained exercise, possibly as a compensatory mechanism to cope with the enhanced production of superoxides and oxyradicals during exhaust ive exercise.