FATTY-ACID UPTAKE IN DIABETIC RAT ADIPOCYTES

The effect of diabetic status and insulin on adipocyte plasma membrane properties and fatty acid uptake was examined. Studies with inhibitor s and isolated adipocyte ghost plasma membranes indicated 9Z, 11E, 13E , 15Z-octatetraenoic acid (cis-parinaric acid) uptake was protein medi ated. Cis-parinaric acid uptake was inhibited by trypsin treatment or incubation with phloretin, and competed with stearic acid. The initial rate, but not maximal uptake, of cis-parinaric acid uptake was enhanc ed two-fold in adipocytes from diabetic rats. Concomitantly, the struc ture and lipid composition of adipocyte ghost membranes was dramatical ly altered. However, the increased initial rate of cis-parinaric acid uptake in the diabetic adipocytes was not explained by membrane altera tions or by a two-fold decrease in cytosolic adipocyte fatty acid bind ing protein (ALBP), unless ALBP stimulated fatty acid efflux. Thus, di abetic status dramatically altered adipocyte fatty acid uptake, plasma membrane structure, lipid composition, and cytosolic fatty acid bindi ng protein.