Transport and distribution of alpha-tocopherol in lymph, serum and liver cells in rats

Rats were cannulated in the major mesenteric lymph duct and given an intraduodenal bolus of unlabeled and alpha-[3H]tocopherol, and [14C]oleic acid in soybean oil. The appearance of alpha-tocopherol in lymph was negligible during the first 2 h and peaked 4-15 h after feeding, whereas no detectable amount was recovered in the portal vein. Intestinal absorption via the lymphatic pathway was 15.4 +/- 8.9% (n = 10) and 45.9 +/- 10.8% (n = 4) for alpha-tocopherol and [14C]oleic acid, respectively. About 99% of alpha-tocopherol in lymph was associated with the chylomicron fraction (d less than 1.006 g/ml). In non-fasting rats, 51% of serum alpha-tocopherol was associated with chylomicrons/VLDL (very-low-density lipoprotein, d less than 1.006 g/ml) and 47% with HDL (high-density lipoprotein, 1.05 less than d less than 1.21 g/ml). Our study revealed that the liver, skeletal muscle and adipose tissue contain approx. 92% of the total mass of alpha-tocopherol measured in ten different organs. Parenchymal and nonparenchymal liver cells contributed to 75% and 25% of the total mass of alpha-tocopherol in the liver, respectively.