Effect of probucol on the composition of lipoproteins and on VLDL apoprotein B turnover.

We studied the effect of probucol on lipoprotein composition and VLDL apo B turnover. In 7 hypercholesterolemic subjects, probucol therapy lowered mean total cholesterol, HDL cholesterol and HDL triglycerides, raised LDL triglycerides and did not change LDL cholesterol. LDL cholesterol:LDL triglycerides mass ratios fell. In all 6 subjects studied by rate-zonal ultracentrifugation, the flotation rate of LDL decreased. The isolated LDL were depleted of cholesteryl esters relative to protein. Thus, there were changes in the physical and chemical properties of LDL. All 6 subjects had reductions in HDL2, with variable changes in HDL3 on zonal ultracentrifugation. Probucol did not cause significant alterations in VLDL apo B turnover in 4 patients. The results suggest that the alterations in HDL probably are not related to changes in the flux of VLDL plasma, but rather may be due to direct effects of the drug on HDL production or catabolism.