The α-tocopherol transfer protein (TTP) plays an important role in the regulation of plasma α-tocopherol concentrations. We hypothesized that hepatic TTP levels would be modulated by dietary vitamin E supplementation and/or by oxidative stress. Mice were fed either a High E (1150 mg RRR-α-tocopheryl acetate/kg diet) or a Low E (11.5 mg/kg diet) diet for 2 wk. High E increased plasma and liver α-tocopherol concentrations approximately 8- and 40-fold, respectively, compared with Low E-fed mice, whereas hepatic TTP increased approximately 20%. Hepatic TTP concentrations were unaffected by fasting (24 h) in mice fed either diet. To induce oxidative stress, chow-fed mice were exposed for 3 d to environmental tobacco smoke (ETS) for 6 h/d (total suspended particulate, 57.4 ± 1.8 mg/m3). ETS exposure, while resulting in pulmonary and systemic oxidative stress, had no effect on hepatic α-tocopherol concentrations or hepatic TTP. Overall, changes in hepatic TTP concentrations were minimal in response to dietary vitamin E levels or ETS-related oxidative stress. Thus, hepatic TTP concentrations may be at sufficient levels such that they are unaffected by either modulations of dietary vitamin E or by the conditions of environmentally related oxidative stress used in the present studies.
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Biochemistry, Genetics and Molecular Biology(all)
- Food Science