ArticleLipids2007
Cytochrome P450-dependent metabolism of vitamin E isoforms is a critical determinant of their tissue concentrations in rats.
Article in Lipids, 2007. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 17 papers.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
17 citing papers in PubMed, 55 citations in OpenAlex.
- Human Vitamin E deficiency, and what is and is not Vitamin E?Free radical biology & medicine · 2024Review
- Article
- Vitamin E and Metabolic Health: Relevance of Interactions with Other Micronutrients.Antioxidants (Basel, Switzerland) · 2022Review
- Synthesis and Liver Microsomal Metabolic Stability Studies of a Fluorine-Substituted δ-Tocotrienol Derivative.ChemMedChem · 2020Article
- Rifampicin, not vitamin E, suppresses parenteral nutrition-associated liver disease development through the pregnane X receptor pathway in piglets.American journal of physiology. Gastrointestinal and liver physiology · 2020Article
- Effects of Calcium and Annatto Tocotrienol Supplementation on Bone Loss Induced by Pantoprazole in Male Rats.Drug design, development and therapy · 2020Article
- Long-Chain Metabolites of Vitamin E: Metabolic Activation as a General Concept for Lipid-Soluble Vitamins?Antioxidants (Basel, Switzerland) · 2018Review
- Synergistic Anticancer Effect of Tocotrienol Combined with Chemotherapeutic Agents or Dietary Components: A Review.International journal of molecular sciences · 2016Review
- Conjugated linoleic acid influences the metabolism of tocopherol in lactating rats but has little effect on tissue tocopherol concentrations in pups.Lipids in health and disease · 2016Article
- Complexity of vitamin E metabolism.World journal of biological chemistry · 2016Review
- Changes in the concentrations of vitamin E analogs and their metabolites in rat liver and kidney after oral administration.Journal of clinical biochemistry and nutrition · 2015Article
- α-Tocopherol does not accelerate depletion of γ-tocopherol and tocotrienol or excretion of their metabolites in rats.Lipids · 2013Article
- Plasma and tissue concentrations of α-tocopherol and δ-tocopherol following high dose dietary supplementation in mice.Nutrients · 2012Article
- Article
- Alpha-tocotrienol is the most abundant tocotrienol isomer circulated in plasma and lipoproteins after postprandial tocotrienol-rich vitamin E supplementation.Nutrition journal · 2012Article
- Vitamin E delta-tocotrienol levels in tumor and pancreatic tissue of mice after oral administration.Pharmacology · 2009Article
- Elevated plasma gamma-tocopherol and decreased alpha-tocopherol in men are associated with inflammatory markers and decreased plasma 25-OH vitamin D.Nutrition and cancer · 2008Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The aim of this study was to clarify the contribution of cytochrome P450 (CYP)-dependent metabolism of vitamin E isoforms to their tissue concentrations. We studied the effect of ketoconazole, a potent inhibitor of CYP-dependent vitamin E metabolism in cultured cells, on vitamin E concentration in rats. Vitamin E-deficient rats fed a vitamin E-free diet for 4 weeks were administered by oral gavage a vitamin E-free emulsion, an emulsion containing alpha-tocopherol, gamma-tocopherol or a tocotrienol mixture with or without ketoconazole. Alpha-tocopherol was detected in the serum and various tissues of the vitamin E-deficient rats, but gamma-tocopherol, alpha- and gamma-tocotrienol were not detected. Ketoconazole decreased urinary excretion of 2,5,7,8-tetramethyl-2(2'-carboxyethyl)-6-hydroxychroman after alpha-tocopherol or a tocotrienol mixture administration, and that of 2,7,8-trimethyl-2(2'-carboxyethyl)-6-hydroxychroman (gamma-CEHC) after gamma-tocopherol or a tocotrienol mixture administration. The gamma-tocopherol, alpha- and gamma-tocotrienol concentrations in the serum and various tissues at 24 h after their administration were elevated by ketoconazole, while the alpha-tocopherol concentration was not affected. The gamma-tocopherol or gamma-tocotrienol concentration in the jejunum at 3 h after each administration was also elevated by ketoconazole. In addition, significant amount of gamma-CEHC was in the jejunum at 3 h after gamma-tocopherol or gamma-tocotrienol administration, and ketoconazole inhibited gamma-tocopherol metabolism to gamma-CEHC in the jejunum. These results showed that CYP-dependent metabolism of gamma-tocopherol and tocotrienol is a critical determinant of their concentrations in the serum and tissues. The data also suggest that some amount of dietary vitamin E isoform is metabolized by a CYP-mediated pathway in the intestine during absorption.
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