Study The Mechanism Of DNP Regulating Insulin Stimulated-glucose Translocation In Skeletal Muscle Cells

Objective:Skeletal muscle is the most important tissue that uptakes glucose, whose normal glycometabolism maintain homostasis. Great attentions have been paid on the signal transduction pathways of glucose transport. It is generally believed that the glucose transport mechanisms indued by insulin and contraction are different. Compared to insulin, the mechanism of how muscle contraction stimulates GLUT4translocation is far from understood. In this study,through the use of DNP to stimulate L6GLUT4myc myoblasts, analog movement signal pathway was observed to increase insulin DNP mechanism.DNP observed increase in insulin action is by increasing the activity of AMPK,inhibit the activity of S6K,thereby increasing insulin signaling molecules Akt and AS160phosphorylation. DNP stimulation verify L6myoblasts can enhance GLUT4myc translocation, mTOR-S6K signal transduction pathway involved in insulin signaling.Methods:1.Application OPD detection GLUT4myc level at the membrane surface.2.Phosphorylation of AMPK, IRS1, Akt, AS160and S6K under insulin or/and DNP treatment were detected in skeletal muscle cells.Results:1. DNP leads to a1.3-to1.4-fold increase in GLUT4myc translocation to the plasma membrane in L6myoblasts after a total of30min treatment period without insulin stimulation.100nM insulin stimulation for20minutes can leads to a2-fold increase in GLUT4myc translocation to the plasma membrane. DNP also causes a3-fold increase in GLUT4myc translocation under100nM insulin stimulation.2. The basis of state level of Akt phosphorylation is very low,and the effect of DNP in the basal state is minimal. Insulin increases the level of Akt phosphorylationon both Ser473and Thr308. DNP can increases the level of Akt phosphorylation under insulin stimulation. 3. DNP stimulates AMPK activity and reduces S6K. Potentiation of insulin-induced AS160phosphorylation by DNP.Insulin stimulated phosphorylation of Akt and AS160. DNP decreased insulin-stimulated IRS1S636/639phosphorylation and enhanced insulin-stimulated Akt and AS160phosphorylation.Conclusion:1. DNP increase GLUT4myc translocation, DNP can increase insulin-stimulated GLUT4myc translocation.2. DNP stimulated AMPK phosphorylation, reduced insulin-stimulated phosphorylation of S6K and reduce IRS1serine phosphorylation.The results suggest:DNP stimulated AMPK phosphorylation, reduced insulin-stimulated phosphorylation of S6K and reduce IRS1serine phosphorylation, increased insulin-stimulated GLUT4myc translocation.