Effect of Glutamate on Lactate-Induced Performance Decrease of Muscular Contraction

Abstract

The accumulation of lactate in exercising muscle causes a fatigue phenomenon with deterioration in muscle performance. In a relative anaerobic condition, it is a normal physiological response to generate lactate for the compensation of NAD/NADH balance of the tissues in order to continue ATP production. The alternative route of lactate metabolism in such a state would be opened via transamination reaction to alanine through pyruvate. Since LDH and GPT are near-equilibrium enzymes, whose kinetics are operated under the simple mass-action law of substrates, it is possible to modulate the metabolism of lactate through the supply of glutamate. In the present experiment, we analyzed the effect of lactate perfusion on muscular contractility and the preventive effect of glutamate on the lactate-induced decrease of muscle performance. The maximal twitch tension was decreased by lactate infusion in contrast to its increase by glutamate and its rapid decrease by alanine infusion. From these results, it can be concluded that the administration of glutamate may improve exercise efficiency through prevention of lactate accumulation in exercising muscle tissues.