Alpha-tocopherol is secreted from rat liver in very low density lipoproteins

J Lipid Res. 1988 Oct;29(10):1359-66.


Three separate studies were carried out to test the hypothesis that rat liver secretes vitamin E (alpha-tocopherol) within very low density lipoproteins (VLDL). i) When the clearance of plasma chylomicrons (CM) and VLDL was blocked by the administration of Triton WR-1339, alpha-tocopherol concentrations increased linearly with time in both classes of triacylglycerol-rich lipoproteins, although accumulation rates within VLDL exceeded those within CM. For fasted rats, appearance of alpha-tocopherol in VLDL persisted at slightly reduced rates. alpha-Tocopherol and triglycerides in the VLDL fraction responded to Triton WR-1339 administration by coordinate increases. In contrast to the situation in serum, alpha-tocopherol concentrations decreased in the liver following injection of Triton. ii) In order to inhibit the secretion of hepatic lipoproteins containing apolipoprotein B (apoB), rats were fed a diet containing orotic acid. This resulted in a reduction of apoB and alpha-tocopherol concentrations in serum and VLDL, whereas the vitamin E content of liver was increased. iii) In primary cultures of hepatocytes, alpha-tocopherol was secreted into the culture media predominantly within VLDL. We, therefore, conclude that the liver secretes alpha-tocopherol within VLDL and in this way contributes to the maintenance of serum vitamin E concentrations.

MeSH terms

  • Animals
  • Apolipoproteins B / analysis
  • Cells, Cultured
  • Chylomicrons / metabolism
  • Culture Media / analysis
  • Lipoproteins, VLDL / blood
  • Lipoproteins, VLDL / metabolism*
  • Liver / analysis
  • Liver / drug effects
  • Liver / metabolism*
  • Male
  • Orotic Acid / pharmacology
  • Polyethylene Glycols / pharmacology
  • Rats
  • Vitamin E / blood
  • Vitamin E / metabolism*


  • Apolipoproteins B
  • Chylomicrons
  • Culture Media
  • Lipoproteins, VLDL
  • Vitamin E
  • Polyethylene Glycols
  • Orotic Acid
  • tyloxapol