EFFECT OF GEMFIBROZIL ON THE CONCENTRATION AND COMPOSITION OF VERY-LOW-DENSITY AND LOW-DENSITY-LIPOPROTEIN SUBFRACTIONS IN HYPERTRIGLYCERIDEMIC PATIENTS

The effect of gemfibrozil treatment on very low (VLDL) and low (LDL) d ensity lipoprotein subfractions has been investigated in 9 moderate hy pertriglyceridemic (HTG) patients (triglyceride (TG) levels 237-426 mg /dl). Three VLDL subfractions, VLDL1 (Sf 175-400), VLDL2 (Sf 100-175) and VLDL3 (Sf 20-100) and 4 LDL subspecies, LDL1 (1.023-1.028 g/ml), L DL2(1.029-1.037 g/ml), LDL3(1.038-1.049 g/ml) and LDL4 (1.050-1.062 g/ ml) were prepared by density gradient ultracentrifugation. High densit y lipoprotein (HDL) chemical composition and lipolytic activities afte r heparin injection were also determined. Gemfibrozil induced a net de crease in VLDL1 and VLDL2 concentrations (P < 0.01). Cholesteryl ester (CE) weight percent was significantly reduced in both VLDL1 and VLDL2 subfractions. VLDL3 concentration and composition were not changed by the treatment. Lipoprotein lipase (LPL) activity was reduced in HTG p atients (P < 0.05). After treatment, LPL activity increased (P < 0.05) but remained lower than in control, normotriglyceridemic (NTG) subjec ts. Furthermore, gemfibrozil increased HDL cholesterol (P < 0.05) and normalised the elevated HDL2 and HDL3 TG content. The increase of LDL cholesterol, often observed after gemfibrozil treatment, was due to a rise in the LDL2 subfraction (1.029 < d < 1.037 g/ml), the main fracti on present in control subjects, However, despite the significant decre ase of total plasma TG (329 mg/dl vs. 174 mg/dl), LDL3 subfraction (1. 038 < d < 1.049 g/ml) was not reduced.