The Effects of Experimental Hepatobiliary Disease on Certain Aspects of Tocopherol Metabolism in the Rat1

Klatskin, Gerald; Tisdale, William A.

doi:10.1172/jci103562

Cited by 3 publications

(1 citation statement)

References 11 publications

(10 reference statements)

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“…The fecal vitamin E metabolites are in non-conjugated forms. In a preliminary experiment, incubation of tocopherols with fecal suspensions under anaerobic conditions failed to produce chain-degradation metabolites, which was consistent with a previous report (19). However, the degradation of tocopherols by intestinal microflora cannot be ruled out.…”

Section: Discussionsupporting

confidence: 91%

Analysis of Multiple Metabolites of Tocopherols and Tocotrienols in Mice and Humans

Zhao

Lee

Cheung

et al. 2010

J. Agric. Food Chem.

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Tocopherols and tocotrienols, collectively known as vitamin E, are essential antioxidant nutrients. The biological fates and metabolite profiles of the different forms are not clearly understood. The objective of this study is to simultaneously analyze the metabolites of different tocopherols and tocotrienols in mouse and human samples. Using HPLC/electrochemical detection and mass spectrometry, 18 tocopherol-derived and 24 tocotrienol-derived side-chain degradation metabolites were identified in fecal samples. Short-chain degradation metabolites, in particular γ-and δ-carboxyethyl hydroxychromans (CEHCs) and carboxymethylbutyl hydroxychromans (CMBHCs) were detected in urine, serum and liver samples, with tocopherols additionally detected in serum and liver samples. The metabolite profiles of tocotrienols and tocopherols were similar, but new tocotrienol metabolites with double bonds were identified. This is the first comprehensive report describing simultaneous analysis of different side-chain metabolites of tocopherols and tocotrienols in mice and humans. Urinary metabolites may serve as useful biomarkers for nutritional assessment of vitamin E.

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Section: Discussionsupporting

confidence: 91%

Analysis of Multiple Metabolites of Tocopherols and Tocotrienols in Mice and Humans

Zhao

Lee

Cheung

et al. 2010

J. Agric. Food Chem.

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The absorption of α-tocopherol in man

Kelleher

Losowsky

1970

Br J Nutr

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I . Physiological oral doses of ~~[5-Me-~H]a-tocopherol were administered to fasting subjects with various disease states, with and without steatorrhoea, and net absorption was calculated by measurement of faecal unabsorbed radioactivity. In each subject studied more than 70 yo of the faecal radioactivity was excreted as unchanged a-tocopherol.2. a-Tocopherol absorption was significantly less in subjects with steatorrhoea (mean 59-4%, range 31-83 %) than in those without steatorrhoea (mean 7z.4%, range 51-86%).Nineteen out of twenty-four subjects with steatorrhoea absorbed less than 65% of the a-tocopherol dose, while twenty-two out of twenty-six subjects without steatorrhoea absorbed more than 65 yo. There was a significant correlation between the severity of steatorrhoea and a-tocopherol absorption. In a wide range of diseases steatorrhoea appeared to be the common factor associated with a decrease in a-tocopherol absorption; however, in subjects after gastric surgery a-tocopherol absorption was often low even in the absence of steatorrhoea, and this may be an important factor in explaining the high incidence of vitamin E deficiency in such patients.3. Radioactivity in the plasma was maximal 6-12 h after dosing. Plasma radioactivity curves were significantly lower in patients with steatorrhoea than in those without steatorrhoea, but there was considerable overlap. In some patients with severe deficiency and severe steatorrhoea there was no detectable plasma response even with considerable absorption of up to 40% of the administered dose. Three patients with severe dietary deficiency of the vitamin and no steatorrhoea also showed a decreased plasma radioactivity.4. Three subjects were studied twice, initially when deficient in a-tocopherol and a second time after repletion with a-tocopherol acetate. There was no evidence for a compensatory mechanism to increase a-tocopherol absorption in a-tocopherol deficiency. 5.A small quantity of the administered dose (almost always less than 6%) was excreted in the urine.

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Vitamin E Saturation Test in Coccidiosis-Infected Rabbits

Diehl

Kistler

1961

The Journal of Nutrition

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The Effects of Experimental Hepatobiliary Disease on Certain Aspects of Tocopherol Metabolism in the Rat1

Cited by 3 publications

References 11 publications

Analysis of Multiple Metabolites of Tocopherols and Tocotrienols in Mice and Humans

Analysis of Multiple Metabolites of Tocopherols and Tocotrienols in Mice and Humans

The absorption of α-tocopherol in man

Vitamin E Saturation Test in Coccidiosis-Infected Rabbits

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