EFFECT OF GLUTAMINE SUPPLEMENTATION ON GLUTAMINE METABOLISM IN EXERCISING MICE

Objective: To approach the effects of glutamine supplementation on plasma and muscle levels of glutamine, and the activities of tissue glutamine synthetase and glutaminase after high intensity exercise. Methods: BAL/C mice were randomly divided into high intensity exercise(2% body weight load) and control groups to swim 2 hours per day for 8 weeks. Results: To compare with control group, high intensity exercise reduced glutamine levels in plasma and muscle by 74% (P0.01) and 79%(P0.01) respectively, and reduced the activity of glutamine synthetase in muscle by 33.5%(P0.01) and enhanced the activity of glutaminase in lymphocytes by 315% (P0.01).To compare with swimming group, glutamine supplementation enhanced glutamine levels in plasma and muscle by 142% (P0.01) and 44.7% (P=0.056) respectively, and enhanced the activity of glutamine synthetase in muscle by 18.0% (P 0.01 ) and reduced the activity of glutaminase in lymphocytes by 25.4%(P0.01). Conclusion: In high intensity exercise, orally supplemented glutamine may raise plasma glutamine levels that might be in relation to glutamine absorbed into circulation; the reduction of glutamine synthesis induced by exercise may be attributed to not only decreased substrate availability but also to decreased glutamine synthetase activity.