Glibenclamide improves postprandial hypertriglyceridaemia in type 2 diabetic patients by reducing chylomicrons but not the very low-density lipoprotein subfraction levels.

AIM: There are scarce data dealing with the degree of postprandial lipaemia after sulphonylurea administration. The aim of this study was to examine the effect of acute glibenclamide administration on postprandial lipaemia in Type 2 diabetic patients.

METHODS: Eight randomly selected Type 2 diabetic individuals, aged 43-65 years (mean, 54 years), who had never received any anti-diabetic drug, were included in the study. Each patient was given a 485 kcal mixed meal (45% fat, 40% carbohydrate and 15% protein) twice on separate days after an overnight fast: once with placebo and once with 5 mg glibenclamide, per os, in a random order. The two tests were performed with an interval of 7 days. Venous blood samples were drawn just before and 2 h, 4 h and 6 h after meal consumption. Total triglyceride levels in plasma, in chylomicrons (CM), in CM-deficient plasma, in very low-density lipoprotein (VLDL) subfractions (VLDL-1, VLDL-2) and in intermediate-density lipoprotein (IDL) were determined. Free fatty acid (FFA) and total cholesterol levels in plasma, as well as high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) cholesterol levels in CM-deficient plasma, were also measured. Finally, serum glucose, insulin and C-peptide concentrations were measured in each sample.

RESULTS: As expected there was a significant decrease in postprandial glycaemia after glibenclamide administration compared to placebo (mean area under the curve values: AUC = 53.3 +/- 18.2 and 69.1 +/- 21.6 mm/h, P = 0.00009). In addition, the mean AUC values of insulin and C-peptide were significantly greater after drug administration. The AUC values of total plasma triglyceride and of CM triglyceride following glibenclamide administration were significantly lower compared to placebo, while the AUC values of postprandial triglyceride in CM-deficient plasma and of postprandial triglyceride in VLDL-1, VLDL-2 and IDL were not different after drug administration compared to placebo. Finally, no significant differences were noted in the AUC values of total cholesterol, LDL cholesterol, HDL cholesterol and plasma FFA levels after glibenclamide administration.

CONCLUSIONS: These results demonstrate that glibenclamide administration improves postprandial hypertriglyceridaemia acutely by reducing postprandial triglycerides of intestinal origin.