INS and Impaired glucose tolerance: Surprisingly, although there were no differences in chow fed mice, the Western diet fed ORMDL3TG male, but not female, mice had impaired glucose tolerance and markedly increased circulating insulin levels, as well as an increase in homeostatic model assessment of insulin resistance (HOMA-IR) (Figure 2D–F), indicating low insulin sensitivity compared to WT littermates fed a Western diet.