Alpha- and gamma-tocopherol levels in lipoproteins fractionated by affinity chromatography.

Abstract

Alpha- and gamma-tocopherol levels of nine women were measured in whole serum and in serum lipoproteins separated by heparin affinity chromatography. Alpha-tocopherol levels (mean +/- SD) in whole serum, low density plus very low density lipoproteins and high density lipoproteins were 10.8 +/- 2.7, 6.4 +/- 1.6 and 4.6 +/- 1.4 (micrograms/ml), respectively. Corresponding values (micrograms/ml) for gamma-tocopherol were 1.2 +/- 0.5, 0.7 +/- 0.3 and 0.6 +/- 0.2. Recoveries of serum alpha- and gamma-tocopherol from the heparin columns were 102 +/- 5% and 105 +/- 7%, respectively. Serum alpha-tocopherol was linearly correlated with components of high density lipoprotein (apolipoproteins, high density lipoprotein cholesterol), but not with serum total lipids or indices of low density lipoprotein, even though high density lipoprotein carried less than half of the serum alpha-tocopherol. However, serum gamma-tocopherol was highly correlated with indices of serum lipids, such as serum cholesterol (r = 0.92, p = 0.005). The coefficient for the correlation of low density lipoprotein (+ very low density lipoprotein) tocopherol with high density lipoprotein tocopherol was r = 0.66 (p = 0.06) for alpha-tocopherol and r = 0.84 (p = 0.004) for gamma-tocopherol. These differences in the relationships of the two tocopherols to lipids and lipoproteins support the view that when the two tocopherols are present at normal dietary levels, gamma-tocopherol partitions between lipoproteins based on their relative lipid content, but a portion of the alpha-tocopherol in high density lipoprotein is specifically bound.