Effects of glyburide treatment on serum lipoprotein and apolipoprotein concentrations and ratios in non-insulin-dependent diabetes mellitus.

Lipoproteins and apolipoproteins were studied in 28 patients with newly detected non-insulin-dependent diabetes mellitus (NIDDM) before and after combined dietary and glyburide treatment. The patients, aged 33 to 67 years and without coronary or other atherosclerotic diseases, displayed fasting blood sugar levels of over 140 mg/dl after four weeks of dietary treatment. Overnight fasting blood samples were collected before the beginning of the trial, after four weeks of dietary treatment, and after four and eight weeks of combined dietary and glyburide treatment. The pretrial levels of total serum cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A1 and A2, and apolipoprotein B were similar to or even lower than those of nondiabetics; however, high-density lipoprotein cholesterol (HDL-C) levels and HDL-C% (the percentage of TC bound to HDL) were significantly lower in the diabetic patients. After combined dietary and glyburide treatment and normalization of blood sugar, apolipoprotein A1 and A2, HDL-C levels, and HDL-C% increased significantly. TC, TG, and LDL-C levels, although not exceeding the normal range, decreased significantly. HDL-C2 and HDL-C3 levels also increased, but the differences did not reach significance. Among the lipid, lipoprotein, and apolipoprotein ratios in the patients, only the ratios HDL-C:LDL-C, apolipoprotein A1:apolipoprotein B, and HDL-C: apolipoprotein B increased significantly as a result of the opposing responses of the protective lipoprotein HDL-C and apolipoprotein A1 and the atherogenic lipoprotein LDL-C and apolipoprotein B. The results demonstrate the favorable effects of combined dietary and sulphonylurea drug treatment on lipoproteins and apolipoproteins in NIDDM patients, thereby reducing coronary and atherosclerotic risks.