The Role of Mitochondria in the Glucose Metabolism

Although mitochondria have been the object of intensive study over many decades, some aspects of their metabolism remain to be fully elucidated, including the role of mitochondria in glucose metabolism. In this regard in addition to glycolysis and gluconeogenesis, the methylglyoxal pathway must be taken in consideration. Thus we will review here the novel insights arisen from some recent achievements on the role of mitochondria on glucose metabolism. In particular we will deal with: 1. The mitochondrial shuttles devoted to transfer reducing equivalents from the cytoplasm to mitochondria including the glycerolphosphate/dihydroxyacetone-phosphate, malate/aspartate, and more importantly, the malate/oxaloacetate and L-lactate/pyruvate shuttles 2. Transport and metabolism in mitochondria of phosphoenolpyruvate with a special emphasis to the mitochondrial pyruvate kinase recently reported. 3. Transport and metabolism in mitochondria of L-lactate with a special emphasis to the mechanism of L-lactate dependent gluconeogenesis due to both the mitochondrial L-lactate dehydrogenase and several L-lactate translocators. 4. Transport and metabolism in mitochondria of D-lactate with emphasis to the D-lactate translocators and the D-lactate dehydrogenase which could account for the removal of the toxic methylglyoxal from cytosol, as well as for D-lactate-dependent gluconeogenesis