Effect of treatment on the concentration of lipoproteins and the postheparin-lipolytic activity in the plasma of noninsulin-dependent diabetics

Summary To study the effect of treatment on plasma lipid and lipoprotein concentration and on postheparin-lipolytic activity (PHLA) in plasma, 26 noninsulin-dependent diabetics were investigated who were treated with maximally effective doses of glibenclamide. The patients were randomly divided into two groups: In group I, glibenclamide was replaced by a long-acting insulin preparation given once daily at variable doses until satisfactory metabolic control was achieved. In group II, glibenclamide was replaced by placebo. At weeks 0, 1, 3, 7, and 12 after change of treatment, the following parameters were determined: Blood glucose, plasma concentrations of cholesterol, triglycerides, phospholipids, HDL cholesterol, very-low-density lipoproteins, intermediate-density lipoporteins, low density lipoproteins, high-density lipoproteins₂ (HDL₂), HDL₃, and PHLA. At week 0, no statistically significant differences existed between group I and group II with respect to all parameters mentioned above. The replacement of glibenclamide by insulin resulted in a continous decrease of blood glucose (p<0.01) with a concomitant increase in HDL₂ (p<0.01) and in PHLA (p<0.01) during the period of investigation. In contrast, replacement of glibenclamide by placebo exerted no significant influence on all determined parameters during 12 weeks. These data suggest that in noninsulin-dependent diabetics, who are inadequately controlled by sulfonylureas, an adequate insulin substitution is necessary to correct, apart from glucose metabolism, the impaired lipoprotein metabolism of diabetes mellitus. Sulfonylureas per se seem not to decrease the HDL₂ fraction nor the PHLA.