Insulin stimulates fatty acid acylation of adipocyte proteins.

Isolated rat adipocytes were incubated with [3H]palmitate in the presence or absence of insulin. Insulin caused marked (20-fold), rapid (T1/2 approximately 15 min), and concentration-dependent labeling of an 80 kilodalton protein. The insulin concentration producing half-maximal labeling was 0.4 ng/ml. The label was removed from the protein by treatment with hydroxylamine indicating the fatty acid was linked to the protein via an oxyester bond. Label removed from the protein co-eluted with palmitate standard by high-performance liquid chromatography. In summary, adipocyte proteins are subject to acylation by exogenous long-chain fatty acids and this process is stimulated by insulin.