No abstract

Lipoproteins were removed from human plasma by ultracentrifugation at a density of 1.225. Three classes of lipoproteins were then separated by 4% Agarose-column chromatography: very low density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL). A sensitive high performance liquid chromatography method with a fluorescence detector was used to estimate alpha-tocopherol in plasma and in column eluates. Total plasma tocopherol was not significantly different in males (n = 6) and females (n = 6) and almost all of the vitamin was recovered in the isolated lipoproteins. Although LDL and HDL were the main carriers of alpha-tocopherol in both males and females, more tocopherol was found in LDL than in HDL in males but the opposite was true in females. The distribution of alpha-tocopherol in males was: VLDL, 8%; LDL, 59%; and HDL, 33% whereas that in females was VLDL, 2%; LDL, 42%; HDL, 56%. The distribution of protein in lipoprotein from males was: VLDL, 4%, LDL, 37%; and HDL, 59% and in females: VLDL, 2%; LDL, 25%; and HDL, 73%. The alpha-tocopherol concentration (expressed as microgram alpha-tocopherol/mg protein) in lipoproteins differed little between the sexes. The values in males were: VLDL, 7.0; LDL, 4.3; and HDL, 1.5, in females: VLDL, 3.9; LDL, 4.7; and HDL, 2.1. The data suggest that the different distribution of alpha-tocopherol in plasma lipoproteins in males and females is due to the different levels of proteins in those lipoprotein fractions. Overall, tocopherol and protein levels were highly correlated in HDL, a lower correlation was found in LDL.

No abstract

Diets rich in linoleic acid (CO) from corn oil, or in linoleic acid and either alpha-linolenic acid (LO) based on linseed oil or n-3 fatty acids (MO) from menhaden oil were fed to male and female Cynomolgus monkeys for 15 wk. In the liver a 40% reduction of alpha-tocopherol occurred in the MO group relative to the CO and LO groups followed by increased formation of lipofuscin in vivo. A four-fold increase of alpha-tocopherol in the MO diet (MO + E) brought the level in the liver to that found with CO and LO. The increased peroxidation in the MO group in the liver phospholipids was associated with the replacement of 60% of the n-6 fatty acids by n-3 fatty acids from menhaden oil. Similar fatty acid profiles were found in groups fed MO and MO + E, respectively. Compared to the CO fed group, feeding alpha-linolenic acid only resulted in a slight incorporation of n-3 fatty acids in the liver membranes mainly due to a direct incorporation of alpha-linolenic acid. However, in monkeys fed menhaden oil more than 30% of the total fatty acids in the liver phospholipids were n-3 fatty acids. The various diets did not influence the activity of liver catalase (EC 1.11.1.6) nor superoxide dismutase (EC 1.15.1.1), but glutathione-peroxidase activity (EC 1.11.1.9) was higher in monkeys fed the MO diet. The catalase activity in females was 20% higher than in males.(ABSTRACT TRUNCATED AT 250 WORDS)

Vitamin E (alpha- and gamma-tocopherol) and total lipid concentrations were determined in the serum of 451 healthy human male and female subjects ranging in age from 19 to 70 years. Mean serum alpha-tocopherol concentration (microgram/ml) was 8.82 +/- 2.84 (SD) and gamma-tocopherol concentration was 1.35 +/- 0.70. The concentration of alpha-tocopherol increased significantly with age, as well as with total lipid; gamma-tocopherol concentration remained unchanged with age. The data also indicated that subjects with higher serum alpha-tocopherol had lower gamma-tocopherol levels and vice versa for subjects with higher gamma levels. A close interrelationship and competition appeared to exist between these two vitamers.