Plasma clearance and net uptake of alpha-tocopherol and low-density lipoprotein by tissues in WHHL and control rabbits

Biochem J. 1992 Oct 1;287 ( Pt 1)(Pt 1):247-54. doi: 10.1042/bj2870247.


The mechanism(s) of uptake of vitamin E (alpha-tocopherol) by tissues is poorly understood. It has, however, been suggested from studies in vitro that the apolipoprotein B/E (apo B/E) receptor pathway for low-density lipoprotein (LDL) may be involved. To investigate the role of the apo B/E receptor pathway in vivo, we have studied the transport and uptake of alpha-tocopherol by tissues in Watanabe Heritable Hyperlipidaemic (WHHL) rabbits, which lack functional LDL (apo B/E) receptors, and controls. [3H]alpha-Tocopherol incorporated within LDL labelled with [14C]sucrose was used in these studies, as this enabled the uptake of both alpha-tocopherol and LDL to be studied independently. The principal findings were as follows. (1) Concentrations of the circulating lipids (including alpha-tocopherol) and LDL were increased and the plasma fractional disappearance rates of alpha-tocopherol and LDL decreased in the WHHL rabbits. (2) The WHHL rabbits clear more LDL and alpha-tocopherol from the circulation than controls do, because of their increased pool sizes of alpha-tocopherol and LDL. (3) The lipoprotein composition of the WHHL rabbits differed from that of the controls, and there was exchange of alpha-tocopherol between the lipoprotein fractions in vivo and in vitro. (4) High-affinity apo B/E receptors were not essential for the uptake of alpha-tocopherol by tissues. (5) Evidence from the plasma-clearance and tissue data suggest that alpha-tocopherol can be taken up by tissues in association with, and also independent of, LDL. We conclude that there are several different mechanisms for the uptake of alpha-tocopherol by tissues, which include receptor-dependent and receptor-independent pathways, independent transport and co-transport of alpha-tocopherol and LDL, and uptake from a number of different lipoproteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport
  • Hyperlipidemias / metabolism
  • Hyperlipidemias / veterinary
  • Lipoproteins, HDL / metabolism
  • Lipoproteins, LDL / metabolism*
  • Metabolic Clearance Rate
  • Rabbits
  • Receptors, Cell Surface / metabolism
  • Receptors, Lipoprotein*
  • Sucrose / metabolism
  • Vitamin E / metabolism*


  • Lipoproteins, HDL
  • Lipoproteins, LDL
  • Receptors, Cell Surface
  • Receptors, Lipoprotein
  • apolipoprotein B,E receptor
  • Vitamin E
  • Sucrose