Plasma High Density Lipoproteins and Lipolytic Enzyme Activities in Diabetic Patients

Abstract

Diabetic patients (80), consecutively selected from an outpatient clinic, were studied with regard to plasma lipoprotein levels, especially HDL [high density lipoprotein]. Patients treated with sulfonylureas had 24% lower HDL cholesterol concentrations (P < 0.01) but only .apprx. 7% lower apolipoprotein AI levels (not significant) than those on insulin treatment. This difference could at least partly be explained by differences in age and type of diabetes. There was no relationship between the degree of diabetic control, as measured by fasting blood glucose levels, and HDL levels. In 2 subgroups of insulin-treated diabetics, selected to represent extremely low and high HDL levels (range 0.5-0.8 and 1.8-2.0 mmol/l, respectively) but matched with regard to age, duration of diabetes, insulin dosage and diabetic control, the activities of lipoprotein lipase and hepatic lipase in postheparin plasma were also recorded. The high HDL group had significantly higher lipoprotein lipase activities (P < 0.01) and significantly lower hepatic lipase activities (P < 0.05) than the low HDL group, supporting the hypothetical roles of these enzymes in HDL metabolism, and offering a tentative mechanism behind the large variability of HDL levels in diabetics.