Acarbose, an α-glucosidase inhibitor, improves insulin resistance in fructose-fed rats

Insulin resistance is one of the determinants of postprandial hyperglycemia. Acarbose is an α-glucosidase inhibitor that delays the absorption of carbohydrates from the small intestine, thereby suppressing postprandial hyperglycemia. Recently, acarbose has been found to reduce the incidence of cardiovascular disease (CVD) in patients with diabetes. These observations suggest that intervention of postprandial hyperglycemia with acarbose is a promising strategy for the prevention of CVD in diabetic patients. However, the effects of acarbose on insulin sensitivity are not fully understood. In this study, we examined whether oral administration of acarbose could improve insulin sensitivity in fructose-fed rats, a widely used insulin-resistant animal model. Although plasma glucose levels remained unchanged during the experiments, serum insulin levels were significantly increased in fructose-fed rats, which were suppressed by 4 weeks of treatment with acarbose. Acarbose treatment also increased high-density lipoprotein levels in fructose-fed rats. Furthermore, treatment of acarbose inhibited the elevation of systolic blood pressure levels in fructose-fed rats. These results indicate that oral administration of acarbose improves insulin sensitivity in fructose-fed rats. Our present study suggests that the cardioprotecive effects of acarbose could be ascribed, at least in part, to its insulin-sensitizing property.