Unlike other diabetic mouse models derived from monogenic disorders or chemical destruction of β-cells, the HFD-induced diabetic mouse model is widely used in studies on pathophysiology of obesity and type 2 diabetes, such as mechanisms of impaired glucose tolerance and insulin resistance, as well as other diabetic complications [35,43], and it is more clinically relevant to obesity-associated type 2 diabetes in humans [35,43]. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.