Biochemical Changes of Muscle Tissues in Exercise: Effect of Training and Glutamate Infusion on Lactate Metabolism

Abstract

In exercise physiology, it is inevitable for the skeletal muscle tissues to generate and accumulate lactate in the tissues, because lactate is the final oxidized product of glycolysis in the relative anerobic condition. The resulting accumulated lactate is supposed to be the main cause of fatigue generation in the exercising muscle tissues. To endure severe exercise, it is known that training can modify lactate metabolism via increase of anerobic threshold. In order to prevent the accumulation of lactate and to activate its clearance in the exercising muscles, it was assumed that the muscle tissue should adapt itself through training to tolerate the high dose of lactate by induction of the related enzymes. The high dose of glutamate infusion prior to exercise would shift GPT and LDH reactions in the direction of lactate elimination. In the present experiment, we determined the changes of enzymic activities such as LDH, GPT and GGTP in muscle tissues of rats after one month swimming training and lactate clearance after strenuous exerise. We compared the glutamate effect on prolonging the survival time. From these results, it was concluded that the enzymes of lactate metabolism are induced in the muscle tissues and lactate clearance is stimulated by training. Moreover, the additional supply of glutamate may improve exercise efficiency via preventing lactate accumulation in exercising muscle tissues.