Heterogeneity of human serum high density lipoproteins on high performance liquid chromatography

A combination method consisting of separation by HPLC using gel permeation columns and selective detection of cholesterol or choline-containing phospholipids was applied to the identification and quantitation of subclasses of high density lipoproteins in human serum. The frequency distribution of peaks in the elution patterns on detection of choline-containing phospholipids in a group (n = 71) of normal males and females showed five maxima. Their particle sizes were determined from the relation between Stokes' diameter and elution volume to be as follows: 122.0 +/- 2.8 A, 110.1 +/- 2.1 A, 97.5 +/- 1.8 A, 86.7 +/- 1.3 A, and 76.3 +/- 16 A. The two larger fractions were found to correspond to HDL2 subclasses, i.e., HDL2b and HDL2a. The other three peaks were found to reflect the subclasses of HDL3 and choline-containing phospholipids in the very high density lipoprotein fraction which sedimented at the bottom on ultracentrifugation at the density of 1.21. Moreover, the existence of these five subclasses in the HDL fraction was confirmed by rechromatography using this combination HPLC method. Our results for the particle sizes of HDL subclasses were confirmed by electron microscopy.