title: Adaptations of glutathione antioxidant system to endurance training are tissue and muscle fiber specific.
abstract: The effect of endurance training on glutathione (GSH) status and antioxidant enzyme system was investigated in skeletal muscle, heart, and liver of female Sprague-Dawley rats pair fed an isocaloric diet. Ten weeks of treadmill training (25 m/min, 10% grade for 2 h/day, 5 days/wk) increased citrate synthase activity in the deep vastus lateralis (DVL) and soleus muscles by 79 and 39%, respectively (P < 0.01), but not in the heart or liver. In DVL, GSH content was increased 33% (P < 0.05) with training, accompanied by a 64% (P < 0.05) increase in glutamate content but no change in cysteine. Trained rats showed a 62 and 27% higher GSH peroxidase (GPX) and superoxide dismutase (SOD) activity, respectively (P < 0.05), in DVL compared with control rats. In contrast, GSH content and glutathione reductase (GR) activity in soleus declined with training (P < 0.05), whereas activities of GPX and SOD remained unchanged. Training did not alter GSH status in the liver or plasma but significantly decreased the GSH-to glutathione disulfide ratio in the heart. In addition, GR activity in the liver and GSH sulfur-transferase activity in the heart and DVL were significantly lower in the trained vs control rats DVL muscle had threefold higher gamma-glutamyl transpeptidase activity compared with other tissues; however no significant alteration was observed in the activity of gamma-glutamyltranspeptidase or gamma-glutamylcysteine synthetase in the liver, heart, or skeletal muscle. These data indicate that endurance training can cause tissue- and muscle fiber-specific adaptation of antioxidant systems and that GSH homeostasis in extrahepatic tissues may be determined by utilization and uptake of GSH via the gamma-glutamyl cycle.
authors.affiliation: Department of Kinesiology, University of Wisconsin-Madison 53706, USA.
authors.forename: C
authors.initials: C
authors.lastname: Leeuwenburgh
authors.forename: J
authors.initials: J
authors.lastname: Hollander
authors.forename: S
authors.initials: S
authors.lastname: Leichtweis
authors.forename: M
authors.initials: M
authors.lastname: Griffiths
authors.forename: M
authors.initials: M
authors.lastname: Gore
authors.forename: L L
authors.initials: LL
authors.lastname: Ji
mesh_terms: D000222:Adaptation, Physiological; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D005260:Female; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D005978:Glutathione / Q000097:blood / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000201:enzymology / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D010088:Oxidoreductases / Q000097:blood / Q000378:metabolism*; D010805:Physical Conditioning, Animal; D010807:Physical Endurance; D051381:Rats; D017207:Rats, Sprague-Dawley; D013379:Substrate Specificity; D005723:gamma-Glutamyltransferase / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010088:Oxidoreductases; D005723:gamma-Glutamyltransferase; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione