Regulation of the α‐tocopherol transfer protein in mice: Lack of response to dietary vitamin E or oxidative stress

• Published in: Lipids 2006-02, Vol.41 (2), p.105-112
• Main Authors: Bella, Deborah L., Schock, Bettina C., Lim, Yunsook, Leonard, Scott W., Berry, Crystal, Cross, Carroll E., Traber, Maret G.
• Format: Article
• Language: English
• Subjects: Animals; Body Weight - drug effects; Carrier Proteins - biosynthesis; Diet; Eating - drug effects; Fasting - physiology; Gene Expression Regulation - drug effects; Liver - metabolism; Male; Mice; Mice, Inbred C57BL; Oxidative Stress - physiology; Tobacco Smoke Pollution; Vitamin E - administration & dosage; Vitamin E - blood
• ISSN: 0024-4201; 1558-9307
• DOI: 10.1007/s11745-006-5077-7

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.