Effects of changeover from voglibose to acarbose on postprandial triglycerides in type 2 diabetes mellitus patients.

INTRODUCTION: In this study, we examined the effects of the alpha-glucosidase inhibitors acarbose and voglibose on postprandial plasma glucose and serum triglyceride levels in patients with type 2 diabetes mellitus. METHODS: Twenty-one Japanese patients with type 2 diabetes were enrolled in this study. Subjects had been treated with voglibose for at least 3 months. They underwent a 400 kcal balanced food meal tolerance test before and 8 weeks after the changeover from voglibose to acarbose. Subjects were divided into two groups: the first group (low-dose group; n=11) was changed over from 0.6 mg/day voglibose to 150 mg/day acarbose, and the other (high-dose group; n=10) from 0.9 mg/day voglibose to 300 mg/day acarbose. RESULTS: The increment rate of postprandial plasma glucose ([plasma glucose 2 hours after test meal - fasting glucose]/fasting glucose) decreased from 34.7%+/-23.9% to 25.0%+/-24.6% (P=0.13) in the low-dose group, and decreased significantly from 56.1%+/-53.1% to 31.5%+/-36.0% (P=0.03) in the high-dose group after changeover. However, there were no significant changes in blood glycated hemoglobin (HbA(1c)) levels before and after changeover in either group. The increment rate of postprandial serum triglyceride (TG) ([serum TG 2 hours after test meal - fasting TG]/fasting TG) decreased significantly only in the high-dose group (52.4%+/-60.0% to 24.3%+/-16.6%) (P=0.05). No significant changes in serum high-density lipoprotein cholesterol levels were observed in either group, whereas serum low-density lipoprotein cholesterol levels decreased significantly from 3.20+/-0.25 to 2.65+/-0.18 mmol/L (P=0.04), only in the high-dose group. CONCLUSIONS: In patients with type 2 diabetes our findings suggest that acarbose 300 mg/day is superior to voglibose 0.9 mg/day in improving postprandial hyperglycemia and hypertriglyceridemia.

Herbal medicine, Hachimi-jio-gan, and its component cinnamomi cortex activate the peroxisome proliferator-activated receptor alpha in renal cells.

Hachimi-jio-gan is widely used to improve several disorders associated with diabetes, but its mechanism remains poorly understood. In an attempt to clarify the mechanism of Hachimi-jio-gan, we investigated the effects of this herbal medicine and its components in transfection studies of CV1 cells, especially nuclear receptor-mediated actions. One half (0.5) mg/ml of Hachimi-jio-gan activated peroxisome proliferator-activated receptor (PPARalpha), mediating the activation by 3.1-fold on DR1 response elements; however, it did not affect PPARgamma, thyroid hormone receptor, androgen receptor, estrogen receptor or RXR. In addition, this activation was observed in a dose-dependent manner. Next, to determine which components of Hachimi-jio-gan activate PPARalpha-mediated transcription, 8 of its components (rehmanniae radix, orni fructus, dioscoreae rhizoma, alismatis rhizoma, hoelen, moutan cortex, cinnamomi cortex, aconiti) were tested. Only cinnamomi cortex (1.0 mg/ml) increased PPARalpha-mediated transcription by 4.1-fold, and this activation was specific for PPAR alpha, and not for other nuclear receptors. Moreover, this PPARalpha-related activation by cinnamomi cortex is specifically observed in renal cells. Taken together, these findings indicate that Hachimi-jio-gan and cinnamomi cortex may have a pharmacological effect through the target site for PPARalpha.