Further evidence for the heterogeneity of high density lipoprotein isolates: HDL2:HDL3 cholesterol ratios and the presence of apolipoprotein B

The ratios were compared of HDL2 to HDL3 cholesterol and the quantitation of apo B in high density lipoprotein (HDL) isolated by the heparin manganese, dextran sulfate, and phosphotungstate precipitation procedures. Thirty-two sera with varied HDL cholesterol concentration were analyzed. Heparin manganese isolates had the highest HDL cholesterol concentrations and the lowest HLD2:HDL3 cholesterol ratios, which differed further from the other isolates at higher HDL concentrations. The corresponding values for dextran sulfate isolates did not differ significantly from phosphotungstate isolates. Heparin manganese and phosphotungstate isolates did not contain apo B, but dextran sulfate isolates contained an average of nine percent of the corresponding serum concentrations of apo B, with no dependence on HDL cholesterol concentration. These differences in HDL2:HDL3 cholesterol and apolipoprotein concentrations are further evidence for the marked heterogeneity of the lipid fraction isolated by various precipitation procedures.