[Possible contribution of amino-acids in myocardium response to hypoxia (author's transl)]

The purpose of the present report is to review current knowledge on amino-acid metabolism during hypoxia in vivo and in vivo, mainly in the myocardium. We have first considered biochemical events occurring in muscles during anoxia either in facultative anaerobic invertebrates or in aerobic vertebrates. In the invertebrate muscle, simultaneous utilization of carbohydrate and amino acids in anoxia leads to ATP formation and accumulation of CO2, alanine and succinate. In aerobic species, ATP production in anoxic conditions is mostly or totally derived from glycolysis, lactate being the end product. Recent studies from various authors have suggested that amino acid utilization may be present in aerobic species exposed to hypoxia and contribute to energy production under these conditions. Experiments using the isolated rat heart preparation have demonstrated the accumulation of alanine and succinate in addition to that of lactate during short period of hypoxia (Fig. 8). The relative importance of these biochemical events in term of energy production is discussed. It is also postulated that the accumulation of alanine and succinate in the myocardium during hypoxia may be involved in other physiological processes.