کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1911061 1046799 2007 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Regulatory mechanisms to control tissue α-tocopherol
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی سالمندی
پیش نمایش صفحه اول مقاله
Regulatory mechanisms to control tissue α-tocopherol
چکیده انگلیسی

To test the hypothesis that hepatic regulation of α-tocopherol metabolism would be sufficient to prevent overaccumulation of α-tocopherol in extrahepatic tissues and that administration of high doses of α-tocopherol would up-regulate extrahepatic xenobiotic pathways, rats received daily subcutaneous injections of either vehicle or 0.5, 1, 2, or 10 mg α-tocopherol/100 g body wt for 9 days. Liver α-tocopherol increased 15-fold in rats given 10 mg α-tocopherol/100 g body wt (mg/100 g) compared with controls. Hepatic α-tocopherol metabolites increased with increasing α-tocopherol doses, reaching 40-fold in rats given the highest dose. In rats injected with 10 mg/100 g, lung and duodenum α-tocopherol concentrations increased 3-fold, whereas α-tocopherol concentrations of other extrahepatic tissues increased 2-fold or less. With the exception of muscle, daily administration of less than 2 mg/100 g failed to increase α-tocopherol concentrations in extrahepatic tissues. Lung cytochrome P450 3A and 1A levels were unchanged by administration of α-tocopherol at any dose. In contrast, lung P-glycoprotein (MDR1) levels increased dose dependently and expression of this xenobiotic transport protein was correlated with lung α-tocopherol concentrations (R2 = 0.88, p < 0.05). Increased lung MDR1 may provide protection from exposure to environmental toxins by increasing alveolar space α-tocopherol.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Free Radical Biology and Medicine - Volume 43, Issue 4, 15 August 2007, Pages 610–618
نویسندگان
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