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

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 lipoproteins, 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 continuous decrease of blood glucose (p less than 0.01) with a concomitant increase in HDL2 (p less than 0.01) and in PHLA (p less than 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.