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)

The objective of this investigation was to find out whether vitamin E deficiency, apart from influencing the lipid component of cellular membranes, also influences the protein component. For that purpose a number of membrane-bound enzymes in the liver of the Pekin duckling were histochemically, cytochemically, and biochemically examined. Furthermore, cells, cellular membranes, and protein particles in membranes were morphometrically investigated. Histochemically five membrane-bound enzymes appeared to be stimulated in vitamin E deficiency: 5'-nucleotidase, glucose-6-phosphatase, isocitrate dehydrogenase (NADP), tetrazolium reductase (NADH), and tetrazolium reductase (NADPH). 5'-Nucleotidase and glucose-6-phosphatase were also investigated cytochemically and biochemically. The cytochemical localization of these enzymes was identical in control and vitamin E-deficient ducklings. Biochemically, a stimulation of these two enzymes also could be demonstrated. The increase per milligram of DNA appeared to be largest whereas the increase per milligram of protein, per milligram of phospholipid, and per milligram of RNA was only half of the increase per milligram of DNA. This can be explained by the 30 per cent increase of the cell volume in vitamin E deficiency leading to an increase of protein, phospholipid, and RNA per cell. The thickness of membranes and the diameter of protein particles in membranes were measured in liver parenchymal cells. In vitamin E deficiency the thickness of the outer mitochondrial membrane and the diameter of protein particles in this membrane were smaller whereas the thickness of the endoplasmic reticular membrane was larger. The increase of the activities of mitochondrial and microsomal enzymes and the decrease of the thickness of the outer mitochondrial membrane and of its protein particles are interpreted to be the result of the influence of free radicals on membranes with electron transport functions. The increase of 5'-nucleotidase activity in the plasma membrane is likely to have a different cause; it may be related to the transport of nucleotides across this membrane.
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PMID:Cellular membranes and membrane-bound enzymes in vitamin E deficiency. A histochemical, cytochemical, biochemical, and morphologic study of the liver of the Pekin duckling. 16 37

1. The effects of vitamin E deficiency, and of vitamin E and selenium deficiency, on rat liver microsomal aminopyrine demethylase activity were investigated. It was found that, over a wide range of substrate concentrations, the enzyme activity in preparations from deficient animals was significantly lower than that in controls. 2. Addition of antioxidants in vitro, either to the homogenization or to the assay media, was without significant effect on the depressed enzyme activity. Castration and alteration in dietary protein concentration were also without effect. The rate of oxidation of NADPH was however, lower in preparations from deficient animals. 3. Lineweaver-Burk plots of the reciprocal of enzyme activity and substrate concentration showed a higher Km value in preparations from vitamin E-deficient animals, irrespective of whether selenium was present; the Vmax. was unaffected. These parameters were unchanged when antioxidants were added in vitro. Induction with phenobarbitone and 3-methylcholanthrene showed large changes in Km value which, for preparations from vitamin E-deficient animals, was higher than that for corresponding controls. 4. Examination of the synergism between NADH and NADPH as donors of reducing equivalents for aminopyrine demethylation showed that vitamin E and selenium were only minimally involved in the phenomenon. However, both the initial rate and the extent of demethylation were significantly lower in vitamin E- and selenium-deficient preparations and both nutrients were required for the restoration of full activity. 5. The significance of these results is discussed in the light of our working hypothesis.
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PMID:The dependence on vitamin E and selenium of drug demethylation in rat liver microsomal fractions. 23 93

The vitamin E deficiency was studied for its effect on the activity of enzymes participating in metabolism of xenobiotics. Experiments with 54 rats have demonstrated that the maintenance of animals on the vitamin-E-deficient diet within 13-14 weeks decreases the activity of microsomal monooxygenases (demethylase and hydroxylase), NADH- and NADPH-reductases, aryl- and aliesterases in the liver and lungs, which is a result of disturbance of hydrophobic and polar interactions in microsomal membranes. Vitamin E deficiency makes the extent of solubilization of these enzymes higher under the influence of deoxycholate and trypsin and intensifies inactivation of these enzymes under the effect of urea. In the lungs and in the liver of the vitamin E deficient rats the content of reduced glutathione decreases as well as the activity of glutathione reductase, glutathione-S-transferase, aldehyde dehydrogenase, while the activity of gamma-glutamyltransferase increases; glutathione disulphide is accumulated.
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PMID:[The effect of vitamin E deficiency on enzyme activity and the status of the membrane fraction of rat liver microsomes]. 258 40

Lipid peroxidation of rat liver microsomal fractions was monitored by its low-level chemiluminescence in preparations from controls and vitamin-E-deficient animals. Measurements were made (a) of the duration of the lag phase tau0 after initiation with NADPH/iron-ADP and (b) of the slope of the chemiluminescence increase. In microsomes with normal vitamin E (alpha-tocopherol) level the lag phase tau0 was substantially increased by ascorbate; in contrast, even an enhanced peroxidation was observed with ascorbate in vitamin-E-deficient microsomes. Therefore, the ascorbate-mediated protection of microsomal membranes against lipid peroxidation is dependent on vitamin E in the membrane. In vitamin E deficiency the pro-oxidant effect of ascorbate was abolished when glutathione (GSH) was present. Likewise, GSH does not prolong the lag phase tau0 in vitamin E deficiency. However, GSH (but not cysteine) exerts an antioxidant effect both in controls and in vitamin E deficiency by decreasing the slope of the chemiluminescence increase during lipid peroxidation. The involvement of GSH in an enzyme-dependent mechanism is suggested.
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PMID:The protection by ascorbate and glutathione against microsomal lipid peroxidation is dependent on vitamin E. 338 50

For 90 days male August rats were kept on 5 diets: (I) balanced semisynthetic, (II) with amino acid unbalance, (III) with excess polyunsaturated fatty acids (PUFA), (IV) with vitamin E deficiency, and (V) polyunbalanced (amino acid unbalance, excess PUFA, vitamin E deficiency). In liver microsomes, the authors studied the kinetics of malonic dialdehyde accumulation in the course of NADPH-dependent lipid peroxidation (LP) and microviscosity of the lipid phase of microsomal membranes according to eximerization of the pyrene fluorescent hydrophobic probe. The microsomes of the animals fed diets I, III and IV showed on the average a 50 to 55% increase in the rate of MDA formation, whereas those of rats on diet V a 78% increase as compared with appropriate characteristics in the animals fed diet I. A good correlation was established between the decrease in the pyrene eximerization rate and accumulation of lipid peroxides: r = 0.09 (P less than 0.05). The possibility of affecting LP in the membranes by the goal oriented modification of the diet is discussed. The participation of proteins, lipids and tocopherol in the maintenance of the membrane structure is described.
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PMID:[Effects of different types of nutritional imbalance on lipid peroxidation and viscosity of membrane lipids]. 396 68

Rat lung and liver microsomes were used to examine the effects of dietary vitamin E deficiency on membrane lipid peroxidation. Microsomes from vitamin-E-deficient rats displayed increased lipid peroxidation in comparison to microsomes from vitamin-E-supplemented controls. The extent of lipid peroxidation, as determined by measurement of thiobarbituric acid reacting materials, was enhanced by addition of reduced iron and ascorbate (or NADPH). Rats fed a vitamin-E-supplemented diet and exposed to 3 ppm NO2 for 7 days did not exhibit increases in microsomal lipid peroxidation compared to air-breathing controls. However, increase were found in microsomes prepared from rats fed a vitamin-E-deficient diet and exposed to NO2. Lung microsomes from vitamin-E-fed rats contained almost 10 times as much vitamin E as liver microsomes when expressed in terms of polyunsaturated fatty acid content. The extent of lipid peroxidation was, in turn, considerably less in lung than in liver microsomes. Lipid peroxidation in lung microsomes from vitamin-E-deficient rats comparable to liver microsomes from vitamin-E-supplemented rats as was the content of vitamin E in these respective microsomal samples. A combination of vitamin E deficiency and NO2 exposure resulted in the greatest increases in lung and liver microsomal lipid peroxidation with the largest relative increases occurring in lung microsomes. An inverse relationship was found between the extent of lipid peroxidation and vitamin E content. Most of the peroxidation in lung microsomes appeared to proceed nonenzymatically whereas peroxidation in liver was largely enzymatic. Vitamin E appears to be assimilated by the lung during oxidant inhalation, but with dietary vitamin E deprivation, the margin for protection in lung may be less than in liver.
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PMID:Influence of vitamin E and nitrogen dioxide on lipid peroxidation in rat lung and liver microsomes. 707 57

Dietetic microangiopathy ("mulberry heart disease") is a common disease of weaned pigs in several countries. It is characterised by sudden death and has been associated with vitamin E deficiency. We investigated whether it could be induced by depleting pigs of vitamin E with or without a mild peroxidative challenge. In a 2 x 2 experiment, the effect on pigs of depletion of alpha-tocopherol and supplementation with alpha-tocopherol-stripped corn oil were investigated. Although dietetic microangiopathy was not induced, there was evidence of lipid peroxidation, as judged by increased concentrations of Fe++(-)induced 4-hydroxynonenal (4-HNE) and decreased amounts of linolenic acid (C18:3, omega-3) in tissue. Reduced glutathione (GSH) can conjugate to 4-HNE in an attempt to detoxify this highly toxic compound. GSH concentrations were decreased in skeletal muscle, but not in heart, of pigs that were depleted of alpha-tocopherol with or without supplementation with corn oil. The activity of glucose-6-phosphate dehydrogenase (G6PDH) was higher in heart than in skeletal muscles. It is postulated that sufficient NADPH may be produced in heart to maintain GSH concentrations at a level sufficient to conjugate the excess 4-HNE produced by alpha-tocopherol deficiency and/or oil supplementation.
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PMID:Feeding corn oil to vitamin E-deficient pigs increases lipid peroxidation and decreases tissue glutathione concentrations. 882 97