GPD1, also known as glycerolphosphate dehydrogenase 1, is a member of the NAD-dependent glycerol-3-phosphate dehydrogenase family. GPD1 catalyzes the reversible redox conversion of dihydroxyacetone phosphate (DHAP), thus plays a critical role in carbohydrate and lipid metabolism. It also reduces nicotine adenine dinucleotide (NADH) to glycerol-3-phosphate (G3P) and NAD+. Meanwhile, GPD1 and mitochondrial glycerol-3-phosphate dehydrogenase also form a glycerol phosphate shuttle that facilitates the transfer of reducing equivalents from the cytosol to mitochondria. Mutations in GPD1 gene are a cause of transient infantile hypertriglyceridemia.