Vitamin E regulation.
OBJECTIVE
Vitamin E deficiency in humans has lead to the discovery of regulatory mechanisms that control plasma alpha-tocopherol concentrations and prevent the accumulation of other molecules with vitamin E-antioxidant activity, such as gamma-tocopherol. This review describes these regulatory mechanisms.


RESULTS
alpha-tocopherol regulatory proteins have been cloned and crystallized and their mechanisms of action are under intense scrutiny. Studies of vitamin E metabolism suggest that xenobiotic metabolism may not only regulate vitamin E concentrations, but that vitamin E may regulate xenobiotic clearance pathways.


CONCLUSIONS
Advances in our understanding of vitamin E nutrition suggest that vitamin E is a potent molecule that is closely regulated such that alpha-tocopherol is at the appropriate tissue concentrations necessary for some as yet to be described functions.
Traber
Maret G
MG
Linus Pauling Institute, Oregon State University Corvallis, Oregon 97331, USA. maret.traber@oregonstate.edu
D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002839:Chromans / Q000378:metabolism; D006801:Humans; D011485:Protein Binding; D011487:Protein Conformation; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism*; D014811:Vitamin E Deficiency / Q000235:genetics / Q000378:metabolism*; D015262:Xenobiotics / Q000378:metabolism
D002352:Carrier Proteins; D002839:Chromans; D018160:Receptors, Cytoplasmic and Nuclear; D015262:Xenobiotics; C017763:alpha-tocopherol transfer protein; C483420:carboxyethyl-hydroxychroman; D014810:Vitamin E