INS and Insulin resistance: We further found both NPY overexpression in PVN and HFD can decrease the average GIR60-120 of euglycemic-hyperinsulinemic clamps, increase total plasma insulin AUC 0 to 120min of IVGTT, HOMA-IR and fasting insulin levels, which indicated that both NPY overexpression and HFD induce peripheral insulin resistance.