In addition to behavior modifications including body weight reduction, aerobic exercise, and smoking cessation, hypoglycemic drugs that reduce acute glucose fluctuations, such as glinides, α-glucosidase inhibitors and DPP-4 inhibitors, and hypoglycemic drugs that ameliorate insulin sensitivity, such as thiazolidinediones and metformin, are expected to improve endothelial function in patients with diabetes mellitus. Here, INS is linked to diabetes mellitus.