The diabetic rat model in this study was induced by two steps: first, high-fat chow feeding to induce obesity, compensatory hyperinsulinemia, and insulin resistance, and second, the administration of low-dose STZ to destroy a part of pancreatic beta cells, leading to a reduction of insulin in serum and causing hyperglycemia. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.