INS and Insulin resistance: To investigate the effects of sex and ET on the development of hypercholesterolemia and insulin resistance in the HFD/APOB-100 mice, serum LDL-cholesterol and HDL-cholesterol levels and their ratio were measured as well as the HOMA-IR was calculated using the following formula: (fasting serum insulin concentration × fasting blood glucose concentration)/22.5 (Fig. 2A–D).