Liver alpha-tocopherol transfer protein and its mRNA are differentially altered by dietary vitamin E deficiency and protein insufficiency in rats.
To study how the expression of alpha-tocopherol transfer protein (alpha-TTP) and its mRNA are affected by protein and vitamin E status, Long-Evans male weanling rats were fed a vitamin E-deficient (DE), high vitamin E (HE, 5 g/kg diet of all-rac-alpha-tocopheryl acetate) or control (C) diet for 12 wk in Experiment 1; and fed a low-protein (LP) or control (C) diet for 6 wk in Experiment 2. The high and deficient vitamin E status of HE and DE groups in Experiment 1 were confirmed by changes in plasma pyruvate kinase activity as well as the concentrations of alpha-tocopherol in plasma and liver. As shown by the Northern and Western Blot Analysis, the expression of alpha-TTP in the liver of the DE group was significantly lower than, while that of the HE group was not different from, that of the controls. In contrast, the alpha-TTP mRNA levels did not differ among the C, DE and HE groups. alpha-Tocopherol in most peripheral tissues of rats fed the LP diet in Experiment 2 was significantly lower than that of the C. Both the alpha-TTP and its mRNA were significantly lower in the LP group than in the C. The results suggested that dietary vitamin E does not affect alpha-TTP gene expression except that the protein levels in the liver were lowered by vitamin E deficiency. On the other hand, protein inadequacy appeared to down-regulate the expression of the alpha-TTP gene.
Shaw
H M
HM
Laboratory of Nutritional Biochemistry, Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan 10716.
Huang
C j
Cj
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D001835:Body Weight; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004032:Diet; D015870:Gene Expression / Q000187:drug effects; D008055:Lipids / Q000097:blood; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D011488:Protein Deficiency / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D014810:Vitamin E / Q000008:administration & dosage* / Q000097:blood; D014811:Vitamin E Deficiency / Q000378:metabolism*
D002352:Carrier Proteins; D008055:Lipids; D012333:RNA, Messenger; C017763:alpha-tocopherol transfer protein; D014810:Vitamin E