134 results on '"Hirche, Frank"'
Search Results
102. Clofibrate Increases Hepatic Triiodothyronine (T3)- and Thyroxine (T4)-Glucuronosyltransferase Activities and Lowers Plasma T3and T4Concentrations in Pigs
- Author
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Luci, Sebastian, primary, Kluge, Holger, additional, Hirche, Frank, additional, and Eder, Klaus, additional
- Published
- 2006
- Full Text
- View/download PDF
103. Interactions of primary fibroblasts and keratinocytes with extracellular matrix proteins: contribution of α2β1 integrin
- Author
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Zhang, Zhi-Gang, primary, Bothe, Ingo, additional, Hirche, Frank, additional, Zweers, Manon, additional, Gullberg, Donald, additional, Pfitzer, Gabriele, additional, Krieg, Thomas, additional, Eckes, Beate, additional, and Aumailley, Monique, additional
- Published
- 2006
- Full Text
- View/download PDF
104. Estimates of individual factors of the tryptophan requirement based on protein and tryptophan accretion responses to increasing tryptophan supply in broiler chickens 8 – 21 days of age
- Author
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Fatufe, Andrew A, primary, Hirche, Frank, additional, and Rodehutscord, Markus, additional
- Published
- 2005
- Full Text
- View/download PDF
105. Gene expression in the liver of rats after feeding diets containing oxidized fats and different levels of vitamin E
- Author
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Hirche, Frank, primary, S�lzle, Andrea, additional, and Eder, Klaus, additional
- Published
- 2004
- Full Text
- View/download PDF
106. Die Wertigkeit der Melanomnachsorge aus der Patientenperspektive. Patients' view of melanoma follow-up
- Author
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Nashan, Dorothee, primary, Kirschner, Franz, additional, Strittmatter, Gerhard, additional, Hirche, Frank, additional, Hensen, Peter, additional, Loquai, Carmen, additional, and Mauch, Cornelia, additional
- Published
- 2004
- Full Text
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107. Fibroblasts in Mechanically Stressed Collagen Lattices Assume a “Synthetic” Phenotype
- Author
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Kessler, Daniela, primary, Dethlefsen, Silke, additional, Haase, Ingo, additional, Plomann, Markus, additional, Hirche, Frank, additional, Krieg, Thomas, additional, and Eckes, Beate, additional
- Published
- 2001
- Full Text
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108. The Interdependence of Solvent, Acceptor Alcohol and Enzyme Source in Transphosphatidylation by Phospholipase D
- Author
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Hirche, Frank, primary and Ulbrich-Hofmann, Renate, additional
- Published
- 2000
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109. Decisive structural determinants for the interaction of proline derivatives with the intestinal H+/peptide symporter
- Author
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Brandsch, Matthias, primary, Knutter, Ilka, additional, Thunecke, Frank, additional, Hartrodt, Bianka, additional, Born, Ilona, additional, Borner, Volker, additional, Hirche, Frank, additional, Fischer, Gunter, additional, and Neubert, Klaus, additional
- Published
- 1999
- Full Text
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110. The interfacial pressure is an important parameter for the rate of phospholipase D catalyzed reactions in emulsion systems
- Author
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Hirche, Frank, primary and Ulbrich-Hofmann, Renate, additional
- Published
- 1999
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111. Phospholipid analogs - chemoenzymatic syntheses and properties as enzyme effectors
- Author
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Ulbrich-Hofmann, Renate, primary, Haftendorn, Regine, additional, Dittrich, Nadeshda, additional, Hirche, Frank, additional, and Aurich, Ines, additional
- Published
- 1998
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112. The influence of organic solvents on phospholipid transformations by phospholipase D in emulsion systems
- Author
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Hirche, Frank, primary, Koch, Michel H.J, additional, König, Stephan, additional, Wadewitz, Tino, additional, and Ulbrich-Hofmann, Renate, additional
- Published
- 1997
- Full Text
- View/download PDF
113. Enzymatic introduction of N-heterocyclic and As-containing head groups into glycerophospholipids
- Author
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Hirche, Frank, primary, Schierhorn, Angelika, additional, Scherer, Gerd, additional, and Ulbrich-Hofmann, Renate, additional
- Published
- 1997
- Full Text
- View/download PDF
114. A moderate excess of dietary lysine lowers plasma and tissue carnitine concentrations in pigs.
- Author
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Fischer, Maren, Hirche, Frank, Kluge, Holger, and Eder, Klaus
- Abstract
This study was performed to investigate whether dietary lysine concentration influences the carnitine status of pigs. Therefore, an experiment with twenty young pigs with an average body weight of 21 kg was performed which were fed either a control diet (9·7 g lysine/kg) or a diet with a moderate excess of lysine (16·8 g lysine/kg). Concentrations of all the other amino acids did not differ between the diets. Pigs fed the high-lysine diet had lower concentrations of free and total carnitine in plasma, liver, kidney and skeletal muscle than control pigs (P < 0·05). Pigs fed the high-lysine diet moreover had an increased concentration of trimethyllysine (TML), a reduced mRNA abundance of TML dioxygenase and reduced concentrations of γ-butyrobetaine (BB) in muscle, indicating that the conversion of TML into BB in muscle was impaired. Concentrations of BB, the metabolic precursor of carnitine, in plasma, liver and kidney were also reduced in pigs fed the high-lysine diet while the activity of BB dioxygenase in kidney was not different and that in liver was even increased compared to control pigs (P < 0·05). In conclusion, this study shows that a moderate dietary excess of lysine lowers plasma and tissue carnitine concentrations in pigs. Reduced concentrations of BB in liver and kidney suggest that the depressed carnitine status was likely caused by a decreased rate of carnitine synthesis due to a diminished availability of carnitine precursor, probably mainly as a result of an impaired BB formation in muscle. [ABSTRACT FROM PUBLISHER]
- Published
- 2009
- Full Text
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115. Homocysteine Thiolactone-Induced Hyperhomocysteinemia Does Not Alter Concentrations of Cholesterol and SREBP-2 Target Gene mRNAs in Rats.
- Author
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Stangl, Gabriele I., Weisse, Kristin, Dinger, Cornelia, Hirche, Frank, Brandsch, Corinna, and Eder, Klaus
- Published
- 2007
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116. Thermally oxidized dietary fat upregulates the expression of target genes of PPAR alpha in rat liver.
- Author
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Sülzle, Andrea, Hirche, Frank, Eder, Klaus, and Sülzle, Andrea
- Subjects
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GENE expression , *VITAMIN E , *RATS , *BLOOD cholesterol - Abstract
Oxidized fats affect animal metabolism in several ways. To gain a comprehensive understanding of the molecular mechanisms underlying the effects of dietary oxidized fats in rats at varying dietary vitamin E concentrations, the gene expression profile of the liver was monitored with an array containing 1176 binding sites for cDNAs. Rats were fed diets with a fresh fat and vitamin E concentrations of 25 or 250 mg alpha-tocopherol/kg (FF25, FF250 rats) or a fat heated at 50 degrees C for 38 d, with vitamin E concentrations of 25 or 250 mg alpha-tocopherol/kg (OF25, OF250 rats) for 63 d. Differences in gene expression were considered to be significant at a ratio of at least 1.4. In the OF25 rats, the expression of 47 genes was altered; in the OF250 rats, the expression of 37 genes was altered, and in the FF250 rats, the expression of 21 genes was altered compared with FF25 rats. In both OF25 and OF250 rats, a series of target genes of the peroxisome proliferator-activated receptor alpha (PPAR alpha) was upregulated. Determination of gene expression of acyl CoA oxidase and activity of catalase confirmed that oxidized fats caused peroxisome proliferation in the liver. In OF25 and OF250 rats, there was also upregulation of 12 and 5 genes involved in xenobiotic metabolism and stress response, of 7 and 7 genes involved in protein metabolism, of 5 and 2 genes encoding intracellular effectors or modulators and of 5 and 6 genes, respectively, encoding activators or repressors of transcription or translation. In conclusion, this study provides indirect evidence that dietary oxidized fats cause an activation of the PPAR alpha, irrespective of the dietary vitamin E concentration. Identification of several other differentially regulated genes may be helpful to understand the effects of oxidized fats on animal metabolism. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
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117. ATP antagonism of thrombin-induced endothelial barrier permeability
- Author
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Gündüz, Dursun, Hirche, Frank, Härtel, Frauke Viola, Rodewald, Christoph Walter, Schäfer, Matthias, Pfitzer, Gabriele, Piper, Hans Michael, and Noll, Thomas
- Subjects
- *
THROMBIN , *MYOSIN , *PERMEABILITY - Abstract
Objectives: Thrombin induces endothelial barrier failure by activating the contractile machinery of endothelial cells. Contractile activation is due to an increase in myosin light chain (MLC) phosphorylation. Here, it was investigated whether stimulation of endothelial cells with ATP can interrupt this thrombin-induced pathomechanism. Methods: In cultured human umbilical vein endothelial cells, cytosolic calcium [Ca2+]i (Fura 2 method), phosphorylation of MLC, isometric tension and permeability for albumin were studied. Results: Thrombin (0.2 U/ml) increased [Ca2+]i from a basal level of 78±8 to 570±63 nM (mean±S.D., n=5, P<0.05), MLC phosphorylation from 71±7 to 163±18%, isometric tension from 157±17 to 232±26 μN, and permeability from 2.8±0.4 to 11.6±1×10−6 cm/s. Co-presence of ATP (10 μM) and thrombin did not alter the [Ca2+]i rise, but reduced MLC phosphorylation to 59.8±10%, isometric tension to 174±14 μN, and permeability to 5.4±0.6×10−6 cm/s. The thrombin-induced rise in MLC phosphorylation was sensitive to reduction of [Ca2+]i It was accompanied by an increase in Rho activation, and was inhibited by Y-27632 (10 μM), a Rho-kinase blocker. The ATP-induced decrease in MLC phosphorylation was not sensitive to [Ca2+]i. It was not accompanied by changes in RhoA activation, and could not by suppressed by Y-27632. Conclusions: ATP antagonizes the Ca2+- and Rho-dependent effects of thrombin on MLC phosphorylation most likely by a Ca2+- and Rho-independent activation of MLC phosphatase. It thereby functionally antagonizes the thrombin-induced increase in monolayer tension and permeability. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
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118. Clofibrate Increases Hepatic Triiodothyronine (T3)- and Thyroxine (T4)-Glucuronosyltransferase Activities and Lowers Plasma T3 and T4 Concentrations in Pigs
- Author
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Luci, Sebastian, Kluge, Holger, Hirche, Frank, and Eder, Klaus
- Abstract
In rats, clofibrate acts as a microsomal enzyme inducer and disrupts the metabolism of thyroid hormones by increasing hepatic glucuronidation of thyroxine. Whether similar effects occur in the pig has not yet been investigated. This study was performed to investigate the effect of clofibrate treatment on metabolism of thyroid hormones in pigs. To this end, an experiment with 18 pigs, which were assigned to two groups, was performed. One group received a control diet, and the other group was fed the same diet supplemented with 5 g of clofibrate/kg for 28 days. Pigs treated with clofibrate had higher hepatic activities of T3- and T4-UDP glucuronosyltransferases (UGT) and lower concentrations of total and free T4 and total T3 in plasma than control pigs (P < 0.05). Weights and histology of the thyroid gland (epithelial height, follicle lumen diameter) did not differ between the two groups, but pigs treated with clofibrate had higher mRNA concentrations of various genes in the thyroid responsive to thyroid-stimulating hormone (TSH) such as TSH receptor, sodium iodine symporter, thyroid peroxidase, and cathepsin B than control pigs (P < 0.05). Pigs treated with clofibrate also had lower hepatic mRNA concentrations of proteins involved in plasma thyroid hormone transport [thyroxine-binding globulin (P < 0.10), transthyretin (P < 0.05), and albumin (P < 0.05)] and thyroid hormone receptor α1 (P < 0.05) than control pigs. In conclusion, this study shows that clofibrate treatment induces a strong activation of T3- and T4-UGT in pigs, leading to increased glucuronidation and markedly reduced plasma concentrations of these hormones, accompanied by a moderate stimulation of thyroid function.
- Published
- 2006
119. PPARγ Ligand Troglitazone Lowers Cholesterol Synthesis in HepG2 and Caco-2 Cells viaa Reduced Concentration of Nuclear SREBP-2
- Author
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Klopotek, Anett, Hirche, Frank, and Eder, Klaus
- Abstract
Cholesterol synthesis in animal cells is regulated by sterol regulatory element-binding protein (SREBP)-2. The objective of this study was to investigate whether activation of peroxisome proliferator-activatedreceptor (PPAR)-γ influences the SREBP-2 dependent cholesterol synthesis in liver and intestinal cells. Therefore, HepG2 and Caco-2 cells were incubated with and without 10 or 30 μM of troglitazone, a synthetic PPARγ agonist, for 4 hrs. Incubation with 10 or 30 μM of troglitazone caused a significant, dose-dependent reduction of cholesterol synthesis in both HepG2 and Caco-2 cells (P < 0.05). HepG2 and Caco-2 cells incubated with 10 or 30 μM of troglitazone had also lower mRNA concentrations and lower nuclear protein concentrations of SREBP-2 than untreated control cells (P < 0.05). mRNA concentrations of the SREBP-2 target genes HMG-CoA reductase and LDL receptor were also reduced in HepG2 and Caco-2 cells treated with 30 μM of troglitazone compared to control cells (P < 0.05). In conclusion, this study shows that PPARγ activation by troglitazone lowers the cholesterol synthesis in HepG2 and Caco-2 cells by reducing the concentration of nuclear SREBP-2 and successive downregulation of its target genes involved in cholesterol synthesis.
- Published
- 2006
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120. Interactions of primary fibroblasts and keratinocytes with extracellular matrix proteins: contribution of α2β1 integrin.
- Author
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Zhi-Gang Zhang, Bothe, Ingo, Hirche, Frank, Zweers, Manon, Gullberg, Donald, Pfitzer, Gabriele, Krieg, Thomas, Eckes, Beate, and Aumailley, Monique
- Subjects
COLLAGEN ,CONNECTIVE tissues ,EXTRACELLULAR matrix proteins ,KERATINOCYTES ,CELL adhesion molecules - Abstract
The α
2 β1 integrin is a collagen-binding protein with very high affinity for collagen I. It also binds several other collagens and laminins and it is expressed by many cells, including keratinocytes and fibroblasts in the skin. In the past, α2 β1 integrin was suggested to be responsible for cell attachment, spreading and migration on monomeric collagen I and contraction of three-dimensional collagen lattices. In view of these functions, normal development and fertility in integrin α2 -deficient mice, which we generated by targeting the integrin α2 gene, came as a surprise. This suggested the existence of compensatory mechanisms that we investigate here using primary fibroblasts and keratinocytes isolated from wild-type and α2 -deficient mice, antibodies blocking integrin function and downregulation of integrin 2 expression. The results show that the α2 β1 integrin is absolutely required for keratinocyte adhesion to collagens whereas for fibroblasts other collagen-binding integrins partially back-up the lack of α2 β1 in simple adhesion to collagen monomers. A prominent requirement for α2 β1 integrins became apparent when fibroblasts executed mechanical tasks of high complexity in three-dimensional surroundings, such as contracting free-floating collagen gels and developing isometric forces in tethered lattices. The deficits observed for α2 -deficient fibroblasts appeared to be linked to alterations in the distribution of force-bearing focal adhesions and deregulation of Rho-GTPase activation. [ABSTRACT FROM AUTHOR]- Published
- 2006
121. Tachysterol 2 increases the synthesis of fibroblast growth factor 23 in bone cells.
- Author
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Ewendt F, Kotwan J, Ploch S, Feger M, Hirche F, Föller M, and Stangl GI
- Abstract
Tachysterol
2 (T2 ) is a photoisomer of the previtamin D2 found in UV-B-irradiated foods such as mushrooms or baker's yeast. Due to its structural similarity to vitamin D, we hypothesized that T2 can affect vitamin D metabolism and in turn, fibroblast growth factor 23 (FGF23), a bone-derived phosphaturic hormone that is transcriptionally regulated by the vitamin D receptor (VDR). Initially, a mouse study was conducted to investigate the bioavailability of T2 and its impact on vitamin D metabolism and Fgf23 expression. UMR106 and IDG-SW3 bone cell lines were used to elucidate the effect of T2 on FGF23 synthesis and the corresponding mechanisms. LC-MS/MS analysis found high concentrations of T2 in tissues and plasma of mice fed 4 vs. 0 mg/kg T2 for 2 weeks, accompanied by a significant decrease in plasma 1,25(OH)2 D and increased renal Cyp24a1 mRNA abundance. The Fgf23 mRNA abundance in bones of mice fed T2 was moderately higher than that in control mice. The expression of Fgf23 strongly increased in UMR106 cells treated with T2 . After Vdr silencing, the T2 effect on Fgf23 diminished. This effect is presumably mediated by single-hydroxylated T2 -derivatives, since siRNA-mediated silencing of Cyp27a1 , but not Cyp27b1 , resulted in a marked reduction in T2 -induced Fgf23 gene expression. To conclude, T2 is a potent regulator of Fgf23 synthesis in bone and activates Vdr. This effect depends, at least in part, on the action of Cyp27a1. The potential of oral T2 to modulate vitamin D metabolism and FGF23 synthesis raises questions about the safety of UV-B-treated foods., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ewendt, Kotwan, Ploch, Feger, Hirche, Föller and Stangl.)- Published
- 2022
- Full Text
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122. Oral intake of 7-dehydrocholesterol increases vitamin D 3 concentrations in the liver and kidney.
- Author
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Kühn J, Hirche F, Geissler S, and Stangl GI
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- Administration, Oral, Animal Feed analysis, Animals, Calcifediol analysis, Calcifediol blood, Calcifediol metabolism, Cholecalciferol analysis, Cholecalciferol blood, Cholesterol analysis, Cholesterol blood, Cholesterol metabolism, Dehydrocholesterols administration & dosage, Dietary Supplements analysis, Male, Mice, Inbred C57BL, Provitamins administration & dosage, Triglycerides analysis, Triglycerides blood, Triglycerides metabolism, Cholecalciferol metabolism, Dehydrocholesterols pharmacology, Kidney metabolism, Liver metabolism, Provitamins pharmacology
- Abstract
Introduction: Due to the high prevalence of vitamin D deficiency, strategies are needed to improve vitamin D status. Food components can affect vitamin D metabolism and have to be considered when estimating the efficacy of vitamin D supplements. 7-dehydrocholesterol (7-DHC) occurs naturally in food, but its impact on vitamin D metabolism has not yet been examined., Methods: Three groups of male C57BL/6 mice (n=12 per group) were placed on a diet that contained 0, 2.5 or 5mg 7-DHC per kg diet over a period of 6 weeks. Vitamin D and other sterols in the serum, skin, liver and kidney were quantified by LC-MS/MS. The relative mRNA abundance of hepatic genes encoding vitamin D hydroxylation enzymes and transporters was analyzed by real-time RT-PCR., Results: We found a substantial dose-dependent increase of non-hydroxylated vitamin D
3 in the liver and kidney of mice fed a diet containing 7-DHC. The vitamin D3 content in the liver was 2.80±0.61pmol/g, 7.34±4.28pmol/g and 12.9±3.58pmol/g in groups that received 0, 2.5 and 5mg/kg 7-DHC, respectively. In the kidney, the vitamin D3 content of these groups was 1.78±1.17pmol/g, 3.55±1.06 and 6.36±2.29pmol/g, respectively. The serum and tissue concentrations of 25-hydroxyvitamin D3 (25(OH)D3 ) remained unaffected by 7-DHC. The relative mRNA data provided no plausible mechanism for the observed effects of 7-DHC on vitamin D3 . All groups of mice had similar concentrations of cholesterol, desmosterol and 7-DHC in their serum and tissues., Conclusion: The current findings provide the first evidence that dietary 7-DHC seems to affect vitamin D metabolism. The underlying mechanism remains elusive and needs further investigation., (Copyright © 2015 Elsevier Ltd. All rights reserved.)- Published
- 2016
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123. Additive effects of lupin protein and phytic acid on aortic calcification in ApoE deficient mice.
- Author
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Schutkowski A, Hirche F, Geissler S, Radtke J, and Stangl GI
- Abstract
Lupin proteins have repeatedly been shown to exhibit lipid lowering properties and reduce aortic calcification in atherosclerosis models. Despite many efforts on its identification, the component which is responsible for the observed effects is still under debate. Phytic acid which is generally associated with lupin protein isolates has currently been described as bioactive plant compound. The objective of the study was to determine the role of associated phytic acid for the described lupin protein effects. A two-factorial study with ApoE knockout mice was conducted in which mice received lupin protein isolate or casein with or without phytase. Phytic acid was added to the casein diets to a final concentration identical to the lupin protein diets. Here we show that the serum concentrations of cholesterol, lathosterol and desmosterol were lower and the faecal bile acid excretion was higher in the groups fed lupin proteins than in the groups fed casein ( p < 0.05). Mice that received the lupin protein diet containing phytic acid were characterized by a lower aortic calcification than mice of the other three groups ( p < 0.05). In conclusion, our results show that the cholesterol lowering properties of lupin protein isolate were not caused by phytic acid. However, the hypocalcific action of lupin proteins appears to depend on the combination of lupin proteins and phytic acid.
- Published
- 2014
- Full Text
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124. Free-range farming: a natural alternative to produce vitamin D-enriched eggs.
- Author
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Kühn J, Schutkowski A, Kluge H, Hirche F, and Stangl GI
- Subjects
- Animal Feed, Animals, Chickens, Diet, Female, Humans, Nutritive Value, Random Allocation, Vitamin D metabolism, Animal Husbandry methods, Cholecalciferol metabolism, Egg Yolk metabolism, Eggs analysis, Sunlight, Vitamin D analogs & derivatives
- Abstract
Objective: Food-based strategies need to be developed to improve the vitamin D status of individuals. Recent studies identified ultraviolet B irradiation as an efficient method to enrich mushrooms and eggs with vitamin D. The aim of this study was to determine whether free-range farming of hens could provide a valuable method to produce vitamin D-enriched eggs., Methods: Laying hens were randomly assigned to three groups of 33 to 34 animals each, and were kept either indoors (indoor group), outdoors (outdoor group), or with an indoor/outdoor option (indoor/outdoor group) over 4 wk., Results: The study shows that the vitamin D3 content of egg yolk was three- to fourfold higher in the groups that were exposed to sunlight (outdoor and indoor/outdoor groups) compared with the indoor group (P < 0.001). Egg yolk from the outdoor group revealed the highest vitamin D3 content, which averaged 14.3 μg/100 g dry matter (DM), followed by that from the indoor/outdoor group (11.3 μg/100 g DM). Yolk from indoor eggs contained only 3.8 μg vitamin D/100 g DM. The 25-hydroxyvitamin D (25[OH]D3) content of egg yolk was also influenced by sunlight exposure, although less pronounced than the vitamin D content (P < 0.05). In contrast, free-range eggs randomly acquired from supermarkets had relatively low vitamin D contents., Conclusion: Free-range farming offers an efficient alternative to fortify eggs with vitamin D, provided that farming conditions are sufficiently attractive for hens to range outside., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
- Full Text
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125. Plasma 25-hydroxyvitamin D and its genetic determinants in relation to incident type 2 diabetes: a prospective case-cohort study.
- Author
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Buijsse B, Boeing H, Hirche F, Weikert C, Schulze MB, Gottschald M, Kühn T, Katzke VA, Teucher B, Dierkes J, Stangl GI, and Kaaks R
- Subjects
- Adult, Aged, Case-Control Studies, Diabetes Mellitus, Type 2 genetics, Female, Genotype, Germany epidemiology, Humans, Incidence, Middle Aged, Polymorphism, Single Nucleotide, Prospective Studies, Risk Factors, Surveys and Questionnaires, Vitamin D blood, Vitamin D genetics, White People genetics, White People statistics & numerical data, Diabetes Mellitus, Type 2 blood, Diabetes Mellitus, Type 2 epidemiology, Vitamin D analogs & derivatives
- Abstract
It is unclear whether vitamin D lowers risk of type 2 diabetes (T2D). In an observational study, we assessed the prospective association between plasma 25-hydroxyvitamin D (25(OH)D) and incident T2D, and evaluated whether it holds up for genetically determined elevated 25(OH)D. We used a case-cohort study nested within the German arm of the European Prospective Investigation into Cancer. From a total cohort of 53,088 participants with a mean follow-up of 6.6 years, we identified a random subcohort of 2,121 participants (57% women) and 1,572 incident cases of T2D. 25(OH)D was measured in baseline plasma samples retrieved from frozen storage. Mean plasma 25(OH)D in the subcohort was 47.1 (5th-95th percentile 19.6-80.7) nmol/L. After controlling for age, sex, center, season of blood draw, education, and lifestyle, the hazard of T2D decreased across increasing plasma concentrations of 25(OH)D (P linear trend<0.0001). The association became non-linear after adjustment for BMI and waist circumference (P non-linearity<0.0001), with the inverse association being restricted to participants with 25(OH)D concentrations below ~45 nmol/L (hazard ratio per 5 nmol/L higher 25(OH)D 0.91, 95% CI 0.84-0.98). A score predicting genetically determined plasma 25(OH)D by weighting four independent single-nucleotide polymorphisms by their effect on 25(OH)D, explained 3.7% of the variance in 25(OH)D. The hazard ratio (95% CI) per 5 nmol/L higher genetically predicted 25(OH)D was 0.98 (0.89-1.08) in the entire study sample and 1.06 (0.93-1.21) in the sub-sample with 25(OH)D<45 nmol/L. This latter finding casts doubt on a strong causal association of 25(OH)D with T2D, but further research in large-scale consortia is needed.
- Published
- 2013
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126. Lupin protein isolate and cysteine-supplemented casein reduce calcification of atherosclerotic lesions in apoE-deficient mice.
- Author
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Weisse K, Brandsch C, Hirche F, Eder K, and Stangl GI
- Subjects
- 5'-Nucleotidase therapeutic use, Amino Acids analysis, Animal Feed, Animals, Atherosclerosis pathology, DNA Primers, Dietary Proteins administration & dosage, Disease Models, Animal, Energy Intake, Lipids blood, Lipids physiology, Mice, Mice, Knockout genetics, Triglycerides metabolism, 5'-Nucleotidase isolation & purification, 5'-Nucleotidase pharmacology, Apolipoproteins E deficiency, Atherosclerosis prevention & control, Calcinosis prevention & control, Caseins pharmacology, Cystine pharmacology
- Abstract
Protein from lupin is supposed to have anti-atherogenic effects due to its lipid-lowering properties in laboratory animals. It is further suggested that the amino acid cysteine plays a crucial role in this aspect. The objective of the present study was to compare the effects of lupin protein and cysteine-supplemented casein with those of casein on atherosclerotic lesion development in apoE-deficient mice. For that purpose, thirty mice were fed an egg albumin-based Western-type diet containing test protein (100 g/kg) for 4 months. ApoE-deficient mice fed the lupin protein or the cysteine-supplemented casein had more than 50 % less aortic calcification than mice fed casein (P < 0.05). The quantified lesion area as a percentage of the total surface area, as well as the collagen and fat content of the lesions were not different between the three groups of mice. The concentration of VLDL TAG was higher in mice fed the lupin protein and the cysteine-supplemented casein than in mice fed casein (P < 0.05). The cholesterol concentrations of VLDL, LDL and HDL from mice fed the lupin protein and cysteine-supplemented casein were not different compared with the mice fed casein. Also, the plasma concentrations of homocysteine, Ca, inorganic phosphate, and the activity of glutathione peroxidase in plasma and liver did not differ between the three groups of mice. The present study shows that lupin protein and cysteine-supplemented casein compared with casein reduce the calcification of atherosclerotic lesions in apoE-deficient mice. This effect seems not to be mediated by effects on plasma lipoproteins, homocysteine and circulating minerals.
- Published
- 2010
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127. Activities of gamma-butyrobetaine dioxygenase and concentrations of carnitine in tissues of pigs.
- Author
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Fischer M, Keller J, Hirche F, Kluge H, Ringseis R, and Eder K
- Subjects
- Animals, Betaine analogs & derivatives, Betaine analysis, Carnitine biosynthesis, Diet, Female, Heart, Kidney enzymology, Kidney metabolism, Liver enzymology, Liver metabolism, Male, Molecular Sequence Data, Muscle, Skeletal chemistry, RNA, Messenger genetics, Reverse Transcriptase Polymerase Chain Reaction, Tissue Distribution, gamma-Butyrobetaine Dioxygenase genetics, Carnitine analysis, Swine metabolism, gamma-Butyrobetaine Dioxygenase metabolism
- Abstract
In contrast to other species, less is known about carnitine homeostasis in the pig. This study was performed to yield information about the site of carnitine synthesis and carnitine concentrations in various tissues of pigs (Sus scrofa). We found that among several pig tissues, a considerable activity of gamma-butyrobetaine dioxygenase (BBD), the last enzyme of carnitine synthesis, exists, like in humans and several other species, only in liver and kidney. Activity of that enzyme in liver and kidney was lower at birth than in the subsequent weeks of life. Highest carnitine concentrations were found in skeletal muscle and heart. Carnitine concentrations in plasma, liver and kidney at birth were higher than in the subsequent weeks of life in spite of the low BBD activity at birth. In conclusion, this study shows that liver and kidney are the major sites of carnitine synthesis and that neonatal pigs do not have an insufficient carnitine status.
- Published
- 2009
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128. L-cysteine down-regulates SREBP-1c-regulated lipogenic enzymes expression via glutathione in HepG2 cells.
- Author
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Bettzieche A, Brandsch C, Hirche F, Eder K, and Stangl GI
- Subjects
- Cell Line, Tumor, Fatty Acid Synthases genetics, Fatty Acid Synthases metabolism, Glucosephosphate Dehydrogenase genetics, Glucosephosphate Dehydrogenase metabolism, Humans, Lipid Metabolism, RNA, Messenger biosynthesis, Stearoyl-CoA Desaturase genetics, Stearoyl-CoA Desaturase metabolism, Sterol Regulatory Element Binding Protein 1 genetics, Cysteine pharmacology, Down-Regulation, Glutathione metabolism, Liver enzymology, Sterol Regulatory Element Binding Protein 1 metabolism
- Abstract
Background/aim: Protein-associated amino acids are supposed to play a role in sterol regulatory element-binding protein (SREBP)-mediated regulation of lipid metabolism. This study investigates the effects of cysteine on expression of SREBP-regulated hepatic genes., Methods: HepG2 cells which are an accepted model for the study of the lipid metabolism were treated with L-cysteine under different conditions., Results: Exposure of cells to L-cysteine reduced the mRNA concentrations of SREBP-1c (-35 to -43%) and its target genes fatty acid synthase (FAS; -20 to -50%), glucose-6-phosphate-dehydrogenase (G6PDH; -31 to -35%), and stearoyl-coenzyme A desaturase (SCD)1 (-34 to -50%). Cells treated with L-cysteine had 47% higher glutathione and 47% lower triglyceride concentrations than control cells. In cells which were concurrently treated with L-cysteine and L-buthionine-[S,R]-sulfoximine, an inhibitor of enzymatic glutathione synthesis, no down-regulation of the gene expression was observed. Pro-oxidant CuSO(4) up-regulated SREBP-1c (+71%), FAS (+165%), G6PDH (+84%) and SCD1 (+96%) mRNA abundance compared to control cells, but when cells were concurrently treated with L-cysteine, the gene expression remained at control level., Conclusions: The results show that L-cysteine rapidly down-regulates the transcription of genes involved in fatty acid biosynthesis via a mechanism that appears to be mediated by an improved glutathione status., ((c) 2008 S. Karger AG, Basel.)
- Published
- 2008
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129. Fasting and caloric restriction increases mRNA concentrations of novel organic cation transporter-2 and carnitine concentrations in rat tissues.
- Author
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Luci S, Hirche F, and Eder K
- Subjects
- Animals, Female, Kidney metabolism, Liver metabolism, Myocardium metabolism, Organic Cation Transport Proteins metabolism, PPAR alpha metabolism, RNA, Messenger metabolism, Random Allocation, Rats, Rats, Sprague-Dawley, Reverse Transcriptase Polymerase Chain Reaction methods, Up-Regulation, Caloric Restriction, Carnitine metabolism, Fasting metabolism, Organic Cation Transport Proteins agonists, PPAR alpha agonists
- Abstract
Background: Recently, we have shown that activation of peroxisome proliferator-activated receptor (PPAR)-alpha by clofibrate leads to an upregulation of novel organic cation transporter (OCTN)-2, a carnitine transporter, and in turn increases the carnitine concentration in the liver of rats. In this study, we tested the hypothesis that fasting and caloric restriction, conditions under which PPARalpha activation also occurs, cause similar effects., Methods: Three groups of rats received the diet either ad libitum (control rats) or 10.5 g diet/day (70% of energy requirement for maintenance, E70 rats) or 6 g diet/day (40% of energy requirement for maintenance, E40 rats) for 10 days. A 4th group received the diet ad libitum for 9 days and was then fasted for 24 h (fasted rats)., Results: Fasted and calorie-restricted rats had increased mRNA concentrations of acyl-CoA oxidase and carnitine palmitoyltransferase-1 in the liver, heart and kidneys compared to control rats (p < 0.05), indicative of activation of PPARalpha in these tissues. E70 rats had increased OCTN2 mRNA concentrations in liver (2.6-fold) and kidneys (1.5-fold) and increased total carnitine concentrations in these tissues compared to control rats. E40 rats had increased OCTN2 mRNA concentrations in the liver (3.3-fold), skeletal muscle (2.2-fold), heart (2.3-fold) and kidneys (3.5-fold) and increased total carnitine concentrations in these four tissues compared to control rats. Fasted rats had increased OCTN2 mRNA concentrations in the liver (4.0-fold), heart (2.1-fold) and kidneys (2.0-fold) and increased total carnitine concentrations in these three tissues (p < 0.05)., Conclusion: The study shows that fasting and caloric restriction lead to an upregulation of OCTN2 in several tissues, probably mediated by activation of PPARalpha. Increased tissue carnitine concentrations in fasted and calorie-restricted rats might be at least in part due to increased uptake of carnitine by OCTN2., ((c) 2008 S. Karger AG, Basel.)
- Published
- 2008
- Full Text
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130. Dietary lupin protein lowers triglyceride concentrations in liver and plasma in rats by reducing hepatic gene expression of sterol regulatory element-binding protein-1c.
- Author
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Spielmann J, Shukla A, Brandsch C, Hirche F, Stangl GI, and Eder K
- Subjects
- Animals, Dietary Proteins metabolism, Down-Regulation, Fatty Acids biosynthesis, Gene Expression Regulation, Lipids blood, Liver drug effects, Male, Random Allocation, Rats, Rats, Sprague-Dawley, Triglycerides blood, Dietary Proteins pharmacology, Lipid Metabolism drug effects, Liver metabolism, Lupinus chemistry, Sterol Regulatory Element Binding Protein 1 metabolism, Triglycerides metabolism
- Abstract
Background: Recently, it has been shown that dietary lupin protein lowers plasma triglyceride concentrations in rats. In this study, we investigated the hypothesis that this effect is due to a downregulation of sterol regulatory element-binding protein (SREBP)-1c, a transcription factor that regulates the expression of lipogenic enzymes in the livers of rats., Methods: Two groups of 12 rats each were fed semisynthetic diets containing 200 g/kg of either casein (control group) or lupin protein from Lupinus albus for 22 days., Results: Rats fed the diet containing lupin protein had lower concentrations of triglycerides in the liver, plasma and VLDL + chylomicrons (p < 0.05). The concentration of protein in VLDL + chylomicrons was also lower in rats fed lupin protein than in rats fed casein (p < 0.05). The mRNA concentrations of SREBP-1c and fatty acid synthase in the liver were lower in rats fed lupin protein than in rats fed casein (p < 0.05). The mRNA concentrations of lipoprotein lipase in the liver did not differ between both groups of rats., Conclusion: This study confirms that a protein isolated from L. albus is strongly hypotriglyceridemic in rats. It is shown for the first time that this effect is at least in part due to a downregulation of SREBP-1c in the liver which in turn leads to a reduction in hepatic fatty acid synthesis., (Copyright (c) 2007 S. Karger AG, Basel.)
- Published
- 2007
- Full Text
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131. PPAR gamma ligand troglitazone lowers cholesterol synthesis in HepG2 and Caco-2 cells via a reduced concentration of nuclear SREBP-2.
- Author
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Klopotek A, Hirche F, and Eder K
- Subjects
- Blotting, Western, Caco-2 Cells, Cell Nucleus drug effects, Cell Nucleus metabolism, Dose-Response Relationship, Drug, Gene Expression, Gene Expression Profiling, Humans, Hydroxymethylglutaryl CoA Reductases drug effects, Hydroxymethylglutaryl CoA Reductases genetics, Intestine, Small drug effects, Intestine, Small metabolism, Liver drug effects, Liver metabolism, RNA, Messenger analysis, Receptors, LDL drug effects, Receptors, LDL genetics, Sterol Regulatory Element Binding Protein 2 metabolism, Troglitazone, Cholesterol biosynthesis, Chromans pharmacology, PPAR gamma agonists, Platelet Aggregation Inhibitors pharmacology, Sterol Regulatory Element Binding Protein 2 drug effects, Thiazolidinediones pharmacology
- Abstract
Cholesterol synthesis in animal cells is regulated by sterol regulatory element-binding protein (SREBP)-2. The objective of this study was to investigate whether activation of peroxisome proliferator-activatedreceptor (PPAR)-gamma influences the SREBP-2 dependent cholesterol synthesis in liver and intestinal cells. Therefore, HepG2 and Caco-2 cells were incubated with and without 10 or 30 microM of troglitazone, a synthetic PPAR gamma agonist, for 4 hrs. Incubation with 10 or 30 microM of troglitazone caused a significant, dose-dependent reduction of cholesterol synthesis in both HepG2 and Caco-2 cells (P < 0.05). HepG2 and Caco-2 cells incubated with 10 or 30 microM of troglitazone had also lower mRNA concentrations and lower nuclear protein concentrations of SREBP-2 than untreated control cells (P < 0.05). mRNA concentrations of the SREBP-2 target genes HMG-CoA reductase and LDL receptor were also reduced in HepG2 and Caco-2 cells treated with 30 microM of troglitazone compared to control cells (P < 0.05). In conclusion, this study shows that PPAR gamma activation by troglitazone lowers the cholesterol synthesis in HepG2 and Caco-2 cells by reducing the concentration of nuclear SREBP-2 and successive downregulation of its target genes involved in cholesterol synthesis.
- Published
- 2006
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132. Interactions of primary fibroblasts and keratinocytes with extracellular matrix proteins: contribution of alpha2beta1 integrin.
- Author
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Zhang ZG, Bothe I, Hirche F, Zweers M, Gullberg D, Pfitzer G, Krieg T, Eckes B, and Aumailley M
- Subjects
- Animals, Cells, Cultured, Collagen Type I metabolism, Collagen Type IV metabolism, Enzyme Activation, Fibroblasts cytology, Focal Adhesions metabolism, Integrin alpha2beta1 genetics, Keratinocytes cytology, Laminin metabolism, Mice, Mice, Inbred C57BL, Mice, Knockout, Skin metabolism, Skin pathology, Stress, Mechanical, cdc42 GTP-Binding Protein metabolism, rhoA GTP-Binding Protein metabolism, Cell Adhesion physiology, Extracellular Matrix Proteins metabolism, Fibroblasts metabolism, Integrin alpha2beta1 metabolism, Keratinocytes metabolism
- Abstract
The alpha2beta1 integrin is a collagen-binding protein with very high affinity for collagen I. It also binds several other collagens and laminins and it is expressed by many cells, including keratinocytes and fibroblasts in the skin. In the past, alpha2beta1 integrin was suggested to be responsible for cell attachment, spreading and migration on monomeric collagen I and contraction of three-dimensional collagen lattices. In view of these functions, normal development and fertility in integrin alpha2-deficient mice, which we generated by targeting the integrin alpha2 gene, came as a surprise. This suggested the existence of compensatory mechanisms that we investigate here using primary fibroblasts and keratinocytes isolated from wild-type and alpha2-deficient mice, antibodies blocking integrin function and downregulation of integrin alpha2 expression. The results show that the alpha2beta1 integrin is absolutely required for keratinocyte adhesion to collagens whereas for fibroblasts other collagen-binding integrins partially back-up the lack of alpha2beta1 in simple adhesion to collagen monomers. A prominent requirement for alpha2beta1 integrins became apparent when fibroblasts executed mechanical tasks of high complexity in three-dimensional surroundings, such as contracting free-floating collagen gels and developing isometric forces in tethered lattices. The deficits observed for alpha2-deficient fibroblasts appeared to be linked to alterations in the distribution of force-bearing focal adhesions and deregulation of Rho-GTPase activation.
- Published
- 2006
- Full Text
- View/download PDF
133. [Lymphocytic infiltration after oral administration of tamsulosin (Alna)].
- Author
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Diesler S, Hirche F, Krieg T, and Hunzelmann N
- Subjects
- Administration, Oral, Adrenergic alpha-Antagonists administration & dosage, Aged, Diagnosis, Differential, Drug Therapy, Combination, Humans, Lymphocytosis pathology, Male, Self Medication, Skin drug effects, Skin pathology, Skin Diseases pathology, Sulfonamides administration & dosage, Tamsulosin, Adrenergic alpha-Antagonists adverse effects, Lymphocytosis chemically induced, Skin Diseases chemically induced, Sulfonamides adverse effects
- Abstract
A 69-year old patient developed dark red plaques located at his trunk, rima ani, both sides of his elbows and on his fingers after oral administration of tamsulosin (Alna). The skin eruptions disappeared and recurred in a reproducible fashion when tamsulosin was briefly discontinued. A skin biopsy taken from a UVA-exposed area on the back showed the histological features of a lymphocytic infiltration. Type-I and type-IV allergic reactions against tamsulosin could not be detected by prick and epicutaneous tests. To our knowledge this is the first report describing a lymphocytic infiltrated caused by tamsulosin. The skin eruptions disappeared and have not recurred since the medication was discontinued.
- Published
- 2005
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134. Effects of megadoses of dietary vitamin E on the antioxidant status of rats fed lard or salmon oil.
- Author
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Flader D, Brandsch C, Hirche F, and Eder K
- Subjects
- Adipose Tissue metabolism, Analysis of Variance, Animals, Antioxidants pharmacology, Dose-Response Relationship, Drug, Glutathione metabolism, Hydroxycholesterols metabolism, In Vitro Techniques, Lipoproteins, LDL drug effects, Liver metabolism, Male, Oxidation-Reduction drug effects, Oxidoreductases metabolism, Rats, Rats, Sprague-Dawley, Thiobarbituric Acid Reactive Substances metabolism, Vitamin E administration & dosage, alpha-Tocopherol metabolism, Antioxidants metabolism, Dietary Fats administration & dosage, Fish Oils administration & dosage, Lipoproteins, LDL metabolism, Vitamin E pharmacology
- Abstract
This study was undertaken to investigate whether megadoses of vitamin E in the diet of rats can have pro-oxidative activity. Two experiments with rats were conducted in which both the dietary vitamin E concentration (Experiment 1: 100; 500; 3000; 10,000 mg all-rac-alpha-tocopheryl acetate/kg, and Experiment 2: 100; 1000; 10,000 mg all-rac-alpha-tocopheryl acetate/kg) and the type of dietary fat (lard vs. salmon oil) were varied. Experimental parameters were the concentrations of thiobarbituric acid-reactive substances, 7 beta-hydroxycholesterol, the activities of several antioxidative enzymes, the concentration of glutathione in the liver, and the lag time during copper-induced low-density lipoprotein (LDL) oxidation. Increasing the dietary vitamin E concentration to 10,000 mg all-rac-alpha-tocopheryl acetate/kg led to a significant reduction of thiobarbituric acid-reactive substances in the liver after feeding salmon oil, and also to a significant reduction in 7 beta-hydroxycholesterol after feeding both dietary fats. Megadoses of vitamin E (3000 and 10,000 mg all-rac-alpha-tocopheryl acetate/kg) also led to a reduction in the activity of superoxide dismutase and the concentration of glutathione in the liver of rats fed salmon oil. The lag time during LDL oxidation was independent of the dietary vitamin E concentration. The study shows that megadoses of vitamin E, far from having pro-oxidative activity, actually increase the anti-oxidative capacity of the liver, especially after ingestion of salmon oil.
- Published
- 2003
- Full Text
- View/download PDF
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