Involved in glycerolipid metabolism. NAD(+) + sn-glycerol 3-phosphate = dihydroxyacetone phosphate + H(+) + NADH Membrane lipid metabolism; glycerophospholipid metabolism. Expressed in young seedlings, flowers and siliques. Expressed at low levels in roots. Belongs to the NAD-dependent glycerol-3-phosphate dehydrogenase family.