Liver -Tocopherol Transfer Protein and Its mRNA Are Differentially Altered by Dietary Vitamin E Deficiency and Protein Insufficiency in Rats

Manuscript received 26 June 1998. Initial reviews completed 23 July 1998. Revision accepted 10 September 1998.

Laboratory of Nutritional Biochemistry, Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan 10716

To study how the expression of -tocopherol transfer protein (-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--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 -tocopherol in plasma and liver. As shown by the Northern and Western Blot Analysis, the expression of -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 -TTP mRNA levels did not differ among the C, DE and HE groups. -Tocopherol in most peripheral tissues of rats fed the LP diet in Experiment 2 was significantly lower than that of the C. Both the -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 -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 -TTP gene.

The Journal of Nutrition Vol. 128 No. 12 December 1998, pp. 2348-2354
Copyright ©1998 by the American Society for Nutritional Sciences

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