Mitochondrial glycerol-3-phosphate dehydrogenase (mGPD) is a Ca2+ -sensitive, FAD-binding protein, located on the outer surface of the inner mitochondrial membrane. mGPD catalyses the oxidation of glycerol-3-phosphate to dihydroxyacetone phosphate (DHAP) with concomitant reduction of the enzyme-bound FAD. Two isoforms have been described for mGPD. Isoform 1 comprises 727aa residues, whereas isoform 2 lacks 126aa residues of the N-terminus. Deficiency of mGPD appears to contribute to the impairment of glucose-stimulated insulin release in several animal models of non-insulin dependent diabetes mellitus.