The effect and mechanism of saturated fatty acids on insulin action in skeletal muscle cells

Objective:To study if saturated fatty acids cause insulin resistance in skeletal muscle cells,and detect whether ribosomal S6 kinase(S6K) is involved in this mechanism.Methods:Palmitic acid coupled to fatty acid-free bovine albumin(BSA) was prepared in a concentration of 5 mmol/L of storage solution.For palmitic acid group,C2C12GLUT4myc skeletal muscle cells were incubated with 0.5 mmol / L palmitic acid for 16 h;for solvent group,the cells were incubated with the same concentration of BSA for 16 h;for the control group,there was no any treatment.The amount of GLUT4myc on the cell surface was measured by an antibody-coupled absorbance assay.Phosphorylation of the insulin signaling molecules,such as insulin receptor substrate(IRS1),protein kinase B(Akt) and S6K were detected by Western blotting.Results:Compared to the control group and solvent group,insulin-stimulated GLUT4myc translocation decreased in palmitic acid group(P0.05);and the level of phosphorylation of Akt decreased,there was no change in the level of S6K phosphorylation,the level of IRS1 S636/639 phosphorylation did not change,either.Conclusion:Palmitic acid can directly cause insulin resistance in skeletal muscle cells,and its mechanism may not involve S6K.