Abstract
AIMS/INTRODUCTION: Dipeptidyl peptidase-4 inhibitors and glinides are effective in reducing postprandial hyperglycemia. However, little information is available on the comparative effects of the two drugs on the levels of postprandial glucose. The aim of the present study was to compare the effects of sitagliptin and nateglinide on meal tolerance tests in drug-naïve patients with type 2 diabetes mellitus. MATERIALS AND METHODS: The study participants were 19 patients with type 2 diabetes mellitus, which was inadequately controlled by diet and exercise. An open-label, prospective, cross-over trial was carried out to compare the effects of single-dose sitagliptin and nateglinide on the postprandial glucose level and its related hormones during meal tests. RESULTS: The change in area under the curve (AUC) of glucose from 0 to 180 min (AUC0-180 min) during the meal test by nateglinide was similar to that by sitagliptin. As expected, the change in active glucagon like peptide-1 was significantly higher after a single-dose of sitagliptin than nateglinide. Then, insulin secretion relative to glucose elevation (ISG) (ΔISG0-180 min: ΔAUC0-180 min insulin/AUC0-180 min glucose) was significantly enhanced by nateglinide compared with sitagliptin. Conversely, glucagon level (ΔAUC0-180 min glucagon) was increased by administration of nateglinide, whereas the glucagon level was reduced by administration of sitagliptin. CONCLUSIONS: The effects of sitagliptin on postprandial glucose levels were similar to those of nateglinide in drug-naïve type 2 diabetes patients. However, the induced changes in insulin, active glucagon-like peptide-1 and glucagon during meal loading suggest that reduction of postprandial hyperglycemia was achieved by the unique effect of each drug.