[Effect of glutamic acid on the anaerobic formation of ATP in the heart muscle]

Abstract

The effect of exogenous glutamic acid on nitrogenous and energetic metabolism of isolated perfused heart of the rat was studied under anoxia. Addition of 5 mM glutamic acid to the perfusate significantly increased the ATP level in anoxic heart. Perfusion of anoxic heart with 5 mM glutamic acid recovered the glutamate and aspartate tissue content and caused augmented production of alanine and succinate, while lactate formation did not change. In the presence of glutamic acid, the glutamine and asparagine contents in the heart-perfusate system markedly increased; however, the ammonia content did not reduce significantly. The effect on glutamic acid was reproduced by its transamination products, 5 mM aspartic and 5 mM alpha-ketoglutaric acids, and was totally eliminated by 2 mM aminooxyacetic acid, an inhibitor of transaminases. These data suggest that the glutamate-induced protective effect of ATP is probably related to the stimulation of substrate phosphorylation in mitochondria, resulting in succinate synthesis that is coupled with glutamate transamination.