EVIDENCE FOR LIPID-SYNTHESIS BY DIHYDROXYACETONE PHOSPHATE-PATHWAY IN RABBIT LUNG SUBCELLULAR-FRACTIONS

Abstract

Lipid synthesis by the lung requires a 3-C skeleton that can be provided by sn-glycerol-3-phosphate derived from glycolysis. Rabbit lung microsomal and mitochondrial fractions were incubated with radiolabeled sn-glycerol-3-P and/or dihydroxyacetone-P. Palmitoyl CoA was used as acyl donor. The lipid fraction was subsequently isolated and radioactive incorporation was determined. Glycerol-3-P and dihydroxyacetone-P were both incorporated into the lipid fraction when each substrate was present alone. During incubation in the presence of equimolar concentrations of both substrates, dihydroxyacetone-P accounted for 41% of the total incorporation. Acylation of dihydroxyacetone phosphate is a potential alternate to the glycerol-3-phosphate pathway for lung lipid synthesis.