Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042875 (vitamin E deficiency)
 916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One hundred and twenty female mice fed diets containing various levels of vitamin E were continuously exposed to 0.5 ppm, 1.0 ppm nitrogen dioxide (NO2), and filtered air for 17 months. Blood, lung, and liver tissues were assayed for glutathione peroxidase (GSH-peroxidase) activity. Exposure to 0.5 ppm NO2 did not affect blood and lung GSH-peroxidase activity; 1.0 ppm NO2 exposure, however, caused suppression of the enzyme. A combination of vitamin E deficiency and 1.0 ppm NO2 exposure resulted in the lowest GSH-peroxidase activities in the blood and lung. High levels of vitamin E in the diet resulted in elevated GSH-peroxidase in the blood and lung. Liver GSH-peroxidase activity was unaffected by either dietary vitamin E or NO2 exposure. No inverse relationship was found between GSH-peroxidase levels and concentrations of organic solvent soluble lipofuscin pigments present in tissues.
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PMID:Long-term NO2 exposure of mice in the presence and absence of vitamin E. II. Effect of glutathione peroxidase. 73 11

The influence of dietary peroxides, vitamin E and selenium on glutathione peroxidase (GSH-Px) activity in the gastrointestinal tract of the rat was investigated. Feeding 7% oxidized stripped corn oid (peroxide value 1,000) in a diet adequate in selenium and vitamin E increased the specific activity of GSH-Px in the stomach mucosa. Feeding oxidized oil produced an increase in the wet weight of the intestinal mucosa which was associated with a decrease in the specific activity of the enzyme. Total GSH-Px activity in the intestinal mucosa was unchanged or moderately increased. These changes were unaffected by the presence of vitamin E in the diet. Dietary peroxides had no effect on GSH-Px activity in the plasma or in the perirenal and paraepididymal adipose tissues. Subacute vitamin E deficiency had no consistent effect on the activity of the enzyme in several tissues examined. In rats fed a Se deficient diet glutathione peroxidase activity decreased markedly in most tissues but only slightly in the intestinal mucosa. The moderate decrease in the intestine may be explained by the accessibility of residual dietary Se to the mucosal cells. The role of Se in the detoxification of peroxides in foods and the response of gastrointestinal GSH-Px to dietary peroxides are discussed.
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PMID:Influence of dietary peroxides, selenium and vitamin E on glutathione peroxidase of the gastrointestinal tract. 126 68

Preliminary experiments confirmed the work of others showing that the total glutathione peroxidase (GSH-px) activity of rat liver supernatant fraction may be resolved into two peaks of activity (peaks I and II) by gel filtration, and that peak I is the selenium-containing enzyme and peak II is another peroxidase indistinguishable from glutathione S-transferase (GST). In selenium and vitamin E deficiency, the total activity of the GSH-px became very low, and the total activity of GST with 1-chloro-2,4-dinitrobenzene (CDNB) as substrate was enhanced. Study of the time course of these changes as deficiency progressed indicated that the stimulus for the rise in GST (CDNB) activity was the fall in GSH-px activity which preceded it. The peroxidase activity of GST was found to reside only in the GST AA, B and B2 forms of the enzyme, which were shown to be respectively a homodimer of the Yc subunit, a homodimer of the Ya subunit and a heterodimer of the YaYc subunit. As vitamin E and selenium deficiency progressed, the B2 and AA forms of the enzyme showed enhanced activity, which was interpreted as implying that the Yc subunit of the enzyme becomes enriched as a consequence of the withdrawal of selenium from the animal's diet. Densitometric measurements of the Yc and Ya subunits confirmed that the amount of the Yc subunit was nearly doubled in selenium deficiency, relative to the Ya subunit.
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PMID:The glutathione S-transferases in selenium and vitamin E deficiency. 400 1

1. Glutatione peroxidase activity (EC 1.11.1.9) and erythrocyte stability were measured in Friesian bull calves which were given for 36 weeks semi-purified diets either adequate or low in selenium or vitamin E or both. 2. Dietary Se or vitamin E content had no effect on growth rate and haematlogical values. None of the calves exhibited clinical deficiency symptoms and serum aspartate amino transferase (EC 2.6.1.1) and creatine phosphokinase (EC 2.7.3.2) activities remained normal. Heart and skeletal muscles of all calves appeared macroscopically and microscopically normal ato autopsy. 3. Glutathione peroxidase activity in plasma, blood and other tissues, except the testis, was significantly lower in calves receiving low dietary Se but was independent of dietary vitamin E content. 4. Plasma vitamin E levels decreased rapidly and to very low levels in calves given low vitamin E diets irrespective of the Se content of the diet. 5. A low dietary vitamin E intake increased the susceptibility of erythrocytes to auto- and peroxidative haemolysis whereas a low Se intake in the presence of adequate vitamin E did not. However, erythrocytes from calves receiving low Se and low vitamin E were more susceptible to peroxidative haemolysis than erythrocytes from calves receiving low vitamin E and adequate Se. The effect of dietary vitamin E content on osmotic haemolysis induced by hypotonic saline was variable. 6. The results suggest that measurement of blood glutathione peroxidase activity and the susceptibility of erythrocytes to auto- or peroxidative haemolysis could be used for the differential diagnosis of subclinical Se and vitamin E deficiency in ruminants.
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PMID:Glutathione peroxidase activity and erythrocyte stability in calves differing in selenium and vitamin E status. 728

A survey of selenium and vitamin E concentrations in horses was conducted at four breeding farms in New York. There were no significant changes in mean blood selenium concentrations in horses at the three sampling dates whereas vitamin E concentrations underwent seasonal fluctuations. The mean blood selenium concentration in this survey for horses fed local feed was 7.7 microgram/dl. Horses fed commercial feed had a mean blood selenium concentration of 15.6 microgram/dl. A 0.94 correlation coefficient was found between blood glutatione peroxidase activity and blood selenium concentrations in horses. The effect of oral and parenteral selenium administration on blood selenium concentrations and blood glutathione peroxidase activity was also investigated. Oral supplementation of 1 mg selenium per day increased blood selenium concentrations above levels associated with myodegeneration in horses and foals. Parenteral supplementation trials with mares at late gestation indicate that only limited amounts of selenium cross the placental barrier. Parenteral supplementation of mares during gestation and lactation or supplementation of foals beginning at birth will increase blood selenium levels in foals above that associated with selenium/vitamin E deficiency.
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PMID:Selenium and vitamin E in horses. 742 74

Lipid peroxides are produced during the enzymatic conversion of arachidonic acid to prostaglandins, thromboxane, prostacyclin, and leukotrienes. These peroxides include hydroperoxides of arachidonic acid formed by lipoxygenase and the prostaglandin endoperoxide intermediates produced by action of prostaglandin endoperoxide synthetase. A number of steps in the arachidonate-dependent prostaglandin pathway are vulnerable to antioxidant affects. Such points in the biosynthetic sequence include prostaglandin endoperoxide synthetase, both the cyclooxygenase and peroxidase activity, prostacyclin synthetase, thromboxane synthetase, and lipooxygenase. Antioxidants added in vitro have been shown to affect prostaglandin synthesis. The present review will stress the limited information concerning the in vivo effect of antioxidants. Studies carried out in the investigator's laboratory on prostaglandin synthesis have utilized rats deficient or replete in vitamin E or propyl gallate (an antioxidant). Differentiation of germ cells in the testis of the male rat is arrested in vitamin E deficiency. Testis microsomal prostaglandin synthesis is altered prior to any overt morphological change. The effect of exogenous antioxidant in either rat testis or mammary gland preparation depends both on the type of antioxidant and the concentration. However, the effects of in vivo and in vitro antioxidant on arachidonate turnover are not identical. The physiological effect of antioxidants on prostaglandin synthesis appear to be specific.
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PMID:Antioxidant effects on the prostaglandin endoperoxide synthetase product profile. 746 Nov 42

alpha-Tocopherol (alpha-TOH), generally regarded as the most important lipid-soluble, chain-breaking antioxidant in human plasma, can also be a pro-oxidant in isolated low-density lipoprotein (LDL) (Bowry V. W.; Stocker R. J. Am. Chem. Soc. 115:6029-6044; 1993). Here we examined whether this pro-oxidant activity of alpha-TOH is of more general relevance. We compared the oxidizability of lipid hydroperoxide-free, in vivo or in vitro alpha-TOH-depleted LDL and high-density lipoprotein (HDL), as well as plasma reconstituted with alpha-TOH-depleted lipoproteins, with that of the corresponding native and alpha-TOH-supplemented samples, using water- and lipid-soluble peroxyl radicals (ROO.), hydroxyl radicals (.OH), Cu2+, the transition metal-containing Ham's F-10 medium, soybean 15-lipoxygenase, and horseradish peroxidase as oxidants. Lipoprotein and plasma oxidizability was assessed by the loss of cholesteryl esters and alpha-TOH and the accumulation of hydroperoxides of cholesteryl esters and phospholipids. Compared to native LDL, HDL, and plasma, the in vivo and in vitro alpha-TOH-depleted counterparts were highly resistant to peroxidation initiation by all oxidants when used at mild radical flux conditions. Wherever tested, the oxidizability of isolated LDL decreased proportionally with decreasing alpha-TOH content. Initiation of LDL lipid oxidation by lipoxygenase and Cu2+ (even up to Cu2+:LDL ratio of 20:1) had an absolute requirement for alpha-TOH. Oxidation of reconstituted plasma with ROO. showed that in the absence of the vitamin, plasma lipids were largely resistant to oxidation, whereas bilirubin and urate oxidized more rapidly. Replenishing the in vitro depleted LDL with alpha-TOH, but not with alpha-tocopherol acetate, fully restored its original content of vitamin E and its oxidizability. Similarly, dietary supplementation with alpha-TOH restored the vitamin content and oxidizability of the in vivo alpha-TOH-depleted lipoproteins and plasma obtained from a patient with familial isolated vitamin E deficiency. Under high fluxes of ROO. and .OH, the activity of alpha-TOH in LDL switched from pro- to anti-oxidant, with the switching point for .OH observed at a lower radical flux than that for ROO.. Together, our results show that alpha-TOH generally makes lipoproteins more reactive towards radical oxidants; this can result in a pro-oxidant activity depending on the specific oxidation conditions.
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PMID:Requirement for, promotion, or inhibition by alpha-tocopherol of radical-induced initiation of plasma lipoprotein lipid peroxidation. 895 30