Adipose glycerolipid formation: effect of nutritional and hormonal states

The potential of glycerolipid formation from sn-glycerol-3-phosphate (GP) and 2-monoacylglycerol (MG) was studied in adipose microsomal fractions under various nutritional and hormonal states. Glycerolipid formation from GP was followed in the presence of [14C]glycerol-3-phosphate and palmitoyl-CoA and was assayed by measuring the formation of butanol-soluble product, consisting mainly of [14C]phosphatidate. Glycerolipid formation from MG was determined in the presence of 2-mono-oleyl glycerol and [14C]palmitoyl-CoA, and was estimated by the formation of both [14C]di- and triacylglycerol. Glycerolipid formation from GP was decreased significantly during food deprivation, in experimental diabetes, in the presence of lipolytic hormone, and during aging. Glycerolipid formation from MG did not change under these conditions and continued at the same rate as observed in control animals. The rate of glycerolipid formation from GP was 7-20 times greater than from MG in the various fat depots. Measurement of the adipose monoacylglycerol concentration did not show any correlation with the glycerolipid formation from MG. The studies suggest that glycerolipid formation from MG is active in various fat depots, and is substantial when glycerolipid formation via GP is impaired.