Involved in the biosynthesis of the sn-glycerol 3-phosphate required for phospholipid synthesis. NAD(+) + sn-glycerol 3-phosphate = dihydroxyacetone phosphate + H(+) + NADH NADP(+) + sn-glycerol 3-phosphate = dihydroxyacetone phosphate + H(+) + NADPH Slightly inhibited by sn-glycerol 3-phosphate. Membrane lipid metabolism; glycerophospholipid metabolism. Cells lacking this gene are auxotrophic for glycerol. Belongs to the NAD-dependent glycerol-3-phosphate dehydrogenase family.