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Yasuyoshi Sayato - One of the best experts on this subject based on the ideXlab platform.
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Selenium methylation and toxicity mechanism of Selenocystine
YAKUGAKU ZASSHI, 1997Co-Authors: Yasuyoshi Sayato, Katsuhiko Nakamuro, Tatsuya HasegawaAbstract:Selenium is an essential trace element and a toxicant for animals. Selenocystine, a selenium-containing amino acid, is one of the chemical forms in which selenium exists in food. This review summarized recent studies on the toxicity mechanism of Selenocystine in experimental animals. Hepatotoxicity is caused by repeated oral administration of Selenocystine. Selenocystine is metabolized by reduced glutathione and/or glutathione reductase to hydrogen selenide via selenocysteine-glutathione selenenyl sulfide. The hydrogen selenide is a key intermediate in the selenium methylation metabolism of inorganic and organic selenium compounds. Accumulation of the hydrogen selenide resulting from inhibition of the selenium methylation metabolism, detoxification metabolic pathway of selenium, is found in animals following repeated administration of a toxic dose of Selenocystine. The excess of the hydrogen selenide produced by inhibition of the selenium methylation metabolism contributes to the hepatotoxicity caused by Selenocystine.
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Identification and metabolism of selenocysteine-glutathione selenenyl sulfide (CySeSG) in small intestine of mice orally exposed to Selenocystine
Archives of Toxicology, 1996Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Yasuyoshi SayatoAbstract:This investigation was carried out to elucidate the chemical form of selenium-containing metabolite in small intestine of ICR male mice orally administered Selenocystine (CySeSeCy). The metabolite in intestinal cytosol of mice treated with CySeSeCy (50 mg/kg) was identified as selenocysteine-glutathione selenenyl sulfide (CySeSG) by high performance liquid chromatography using a gel filtration and reversed phase column. Hydrogen selenide formation was caused as a result of the anaerobic reaction between the CySeSG and liver cytosol containing selenocysteine β-lyase, which specifically acts on selenocysteine (CySeH). Effects of GSH or glutathione reductase on hydrogen selenide formation from CySeSG reacted with the liver cytosol were examined. The CySeSG was nonenzymatically reduced to CySeH by excess GSH in the liver cytosol. It was also recognized that CySeSG was enzymatically reduced to CySeH by glutathione reductase in the presence of NADPH. These results indicate that the chemical form of this metabolite is CySeSG, which has a molecular weight of 473, the CySeSG is then reduced by excess GSH and/or gluta- thione reductase yielding CySeH, which is decomposed by selenocysteine β-lyase to hydrogen selenide. CySeSG may be a stable precursor of hydrogen selenide in animals.
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Chemical form of selenium-containing metabolite in small intestine and liver of mice following orally administered Selenocystine
Archives of Toxicology, 1995Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Makoto Mihara, Yasuyoshi SayatoAbstract:The chemical form of a selenium-containing metabolite in the small intestine following a single oral administration of Selenocystine was investigated with ICR male mice. Selenium content in the small intestine of animals treated with 50 mg/kg Selenocystine significantly increased 15 min, 1 h and 6 h after treatment. In contrast, Selenocystine significantly depressed the intestinal reduced glutathione (GSH) level at 1 h after administration. A significant negative correlation between the selenium level and the level of GSH in the small intestine was observed ( r =−0.83, p
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chemical form of selenium containing metabolite in small intestine and liver of mice following orally administered Selenocystine
Archives of Toxicology, 1995Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Makoto Mihara, Yasuyoshi SayatoAbstract:The chemical form of a selenium-containing metabolite in the small intestine following a single oral administration of Selenocystine was investigated with ICR male mice. Selenium content in the small intestine of animals treated with 50 mg/kg Selenocystine significantly increased 15 min, 1 h and 6 h after treatment. In contrast, Selenocystine significantly depressed the intestinal reduced glutathione (GSH) level at 1 h after administration. A significant negative correlation between the selenium level and the level of GSH in the small intestine was observed (r=−0.83, p<0.001). Analysis of the intestinal metabolite of Selenocystine showed that selenium-containing metabolites elute in two fractions from a Sephadex G-25 column: the low-molecular fraction (peak I) contained the Selenocystine, while the high-molecular fraction (peak II) contained selenocysteine-containing metabolite. An in vitro experiment was performed to gain insight into the mechanism for selenocysteine-containing metabolite production in the intestinal cytosol. When Selenocystine or selenocysteine reacted with excess GSH in the presence of intestinal homogenate, the peak II fraction which involved the selenocysteine-containing metabolite was recognized in the Sephadex G-25 chromatogram. From an examination of the distribution of the selenocysteine-containing metabolite, it was recognized that this metabolite exists in plasma and liver cytosol of mice after oral administration of Selenocystine. These results suggested that the mice treated with Selenocystine produce selenocysteine-containing metabolite by reaction of Selenocystine with excess GSH in the small intestine, and the metabolite is then transported to the liver through blood plasma.
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toxicity and chemical form of selenium in the liver of mice orally administered Selenocystine for 90 days
Archives of Toxicology, 1994Co-Authors: Tatsuya Hasegawa, Katsuhiko Nakamuro, Makoto Mihara, Shinjiro Taniguchi, Yasuyoshi SayatoAbstract:The subacute oral toxicity of Selenocystine and chemical form of selenium in the liver following exposure to this compound were assessed in ICR male mice. Animals were dosed 6 days/week for 30, 60 or 90 days with 0, 5, 10 or 15 mg/kg per day. Body weight gain decreased with dosage. The activities of aspartate aminotransferase and alanine aminotransferase in plasma were significantly elevated at the highest dose level after 60 days and at the two higher dose levels after 90 days of exposure. However, the level of selenium content in the liver was the same at the two higher dosages at both 60 and 90 days of exposure. The subcellular distribution of selenium in the liver from mice treated with Selenocystine showed that the major part of the total selenium content, 68.3–72.1%, existed in the cytosolic fraction. Sephadex G-150 chromatograms of liver cytosol of the animals administered Selenocystine revealed three selenium-containing fractions which involve glutathione peroxidase (molecular weight 80 000) high molecular (molecular weight 55 000–60 000) and low molecular (molecular weight <10 000) substances. Selenium content and acid-volatile selenium content in the high molecular weight fraction increased with exposure time to Selenocystine. Thus, in a subacute toxicity study Selenocystine given for 90 days caused hepatic damage in mice, depending on the acid-volatile selenium content in the liver cytosol.
Katsuhiko Nakamuro - One of the best experts on this subject based on the ideXlab platform.
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Enhancement of Hydroxyl Radical Formation from Superoxide Anion Radical in the Presence of Organic Selenium Compounds
Journal of Health Science, 2001Co-Authors: Tomofumi Okuno, Hitoshi Ueno, Hitoshi Kawai, Tatsuya Hasegawa, Katsuhiko NakamuroAbstract:The generation of superoxide anion or hydroxyl radical derived from the organic selenium compounds selenomethionine, selenoethionine, Selenocystine, selenocystamine and selenocysteine-glutathione selenenyl sulfide (CySeSG) was investigated by the electron spin resonance (ESR) technique with 5, 5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trapping agent. The intensity of ESR signals of DMPO-OOH adduct formed by the reaction of the hypoxanthine/xanthine oxidase reaction system with DMPO decreased in the presence of selenomethionine or selenoethionine. However, the decrease of this ESR signal intensity was not due to superoxide anion-scavenging ability of these selenium compounds. When selenomethionine or selenoethionine existed in the superoxide anion generating system at a higher concentration, a new ESR signal was recognized. This signal disappeared with the addition of a hydroxyl radical-scavenging reagent and was similar to the signal of DMPO-OH adduct. The lack of structural change in selenomethionine or selenoethionine following reaction with components of the superoxide anion generating system suggested that these selenium compounds act as a catalyst. Such a phenomenon was not observed in the superoxide anion generating system in the presence of Selenocystine, selenocystamine or CySeSG. These findings suggested that coexistence of selenomethionine or selenoethionine under mammalian physiological conditions generating superoxide anion may possibly form a hydroxyl radical.
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Selenium methylation and toxicity mechanism of Selenocystine
YAKUGAKU ZASSHI, 1997Co-Authors: Yasuyoshi Sayato, Katsuhiko Nakamuro, Tatsuya HasegawaAbstract:Selenium is an essential trace element and a toxicant for animals. Selenocystine, a selenium-containing amino acid, is one of the chemical forms in which selenium exists in food. This review summarized recent studies on the toxicity mechanism of Selenocystine in experimental animals. Hepatotoxicity is caused by repeated oral administration of Selenocystine. Selenocystine is metabolized by reduced glutathione and/or glutathione reductase to hydrogen selenide via selenocysteine-glutathione selenenyl sulfide. The hydrogen selenide is a key intermediate in the selenium methylation metabolism of inorganic and organic selenium compounds. Accumulation of the hydrogen selenide resulting from inhibition of the selenium methylation metabolism, detoxification metabolic pathway of selenium, is found in animals following repeated administration of a toxic dose of Selenocystine. The excess of the hydrogen selenide produced by inhibition of the selenium methylation metabolism contributes to the hepatotoxicity caused by Selenocystine.
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Identification and metabolism of selenocysteine-glutathione selenenyl sulfide (CySeSG) in small intestine of mice orally exposed to Selenocystine.
Archives of Toxicology, 1996Co-Authors: T Hasegawa, Katsuhiko Nakamuro, T Okuno, Y SayatoAbstract:This investigation was carried out to elucidate the chemical form of selenium-containing metabolite in small intestine of ICR male mice orally administered Selenocystine (CySeSeCy). The metabolite in intestinal cytosol of mice treated with CySeSeCy (50 mg/kg) was identified as selenocysteine-glutathione selenenyl sulfide (CySeSG) by high performance liquid chromatography using a gel filtration and reversed phase column. Hydrogen selenide formation was caused as a result of the anaerobic reaction between the CySeSG and liver cytosol containing selenocysteine beta-lyase, which specifically acts on selenocysteine (CySeH). Effects of GSH or glutathione reductase on hydrogen selenide formation from CyseSG reacted with the liver cytosol were examined. The CySeSG was nonenzymatically reduced to CySeH by excess GSH in the liver cytosol. It was also recognized that CySeSG was enzymatically reduced to CySeH by glutathione reductase in the presence of NADPH. These results indicate that the chemical form of this metabolite is CySeSG, which has a molecular weight of 473, the CySeSG is then reduced by excess GSH and/or glutathione reductase yielding CySeH, which is decomposed by selenocysteine beta-lyase to hydrogen selenide. CySeSG may be a stable precursor of hydrogen selenide in animals.
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Identification and metabolism of selenocysteine-glutathione selenenyl sulfide (CySeSG) in small intestine of mice orally exposed to Selenocystine
Archives of Toxicology, 1996Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Yasuyoshi SayatoAbstract:This investigation was carried out to elucidate the chemical form of selenium-containing metabolite in small intestine of ICR male mice orally administered Selenocystine (CySeSeCy). The metabolite in intestinal cytosol of mice treated with CySeSeCy (50 mg/kg) was identified as selenocysteine-glutathione selenenyl sulfide (CySeSG) by high performance liquid chromatography using a gel filtration and reversed phase column. Hydrogen selenide formation was caused as a result of the anaerobic reaction between the CySeSG and liver cytosol containing selenocysteine β-lyase, which specifically acts on selenocysteine (CySeH). Effects of GSH or glutathione reductase on hydrogen selenide formation from CySeSG reacted with the liver cytosol were examined. The CySeSG was nonenzymatically reduced to CySeH by excess GSH in the liver cytosol. It was also recognized that CySeSG was enzymatically reduced to CySeH by glutathione reductase in the presence of NADPH. These results indicate that the chemical form of this metabolite is CySeSG, which has a molecular weight of 473, the CySeSG is then reduced by excess GSH and/or gluta- thione reductase yielding CySeH, which is decomposed by selenocysteine β-lyase to hydrogen selenide. CySeSG may be a stable precursor of hydrogen selenide in animals.
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Chemical form of selenium-containing metabolite in small intestine and liver of mice following orally administered Selenocystine
Archives of Toxicology, 1995Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Makoto Mihara, Yasuyoshi SayatoAbstract:The chemical form of a selenium-containing metabolite in the small intestine following a single oral administration of Selenocystine was investigated with ICR male mice. Selenium content in the small intestine of animals treated with 50 mg/kg Selenocystine significantly increased 15 min, 1 h and 6 h after treatment. In contrast, Selenocystine significantly depressed the intestinal reduced glutathione (GSH) level at 1 h after administration. A significant negative correlation between the selenium level and the level of GSH in the small intestine was observed ( r =−0.83, p
Tatsuya Hasegawa - One of the best experts on this subject based on the ideXlab platform.
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Enhancement of Hydroxyl Radical Formation from Superoxide Anion Radical in the Presence of Organic Selenium Compounds
Journal of Health Science, 2001Co-Authors: Tomofumi Okuno, Hitoshi Ueno, Hitoshi Kawai, Tatsuya Hasegawa, Katsuhiko NakamuroAbstract:The generation of superoxide anion or hydroxyl radical derived from the organic selenium compounds selenomethionine, selenoethionine, Selenocystine, selenocystamine and selenocysteine-glutathione selenenyl sulfide (CySeSG) was investigated by the electron spin resonance (ESR) technique with 5, 5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trapping agent. The intensity of ESR signals of DMPO-OOH adduct formed by the reaction of the hypoxanthine/xanthine oxidase reaction system with DMPO decreased in the presence of selenomethionine or selenoethionine. However, the decrease of this ESR signal intensity was not due to superoxide anion-scavenging ability of these selenium compounds. When selenomethionine or selenoethionine existed in the superoxide anion generating system at a higher concentration, a new ESR signal was recognized. This signal disappeared with the addition of a hydroxyl radical-scavenging reagent and was similar to the signal of DMPO-OH adduct. The lack of structural change in selenomethionine or selenoethionine following reaction with components of the superoxide anion generating system suggested that these selenium compounds act as a catalyst. Such a phenomenon was not observed in the superoxide anion generating system in the presence of Selenocystine, selenocystamine or CySeSG. These findings suggested that coexistence of selenomethionine or selenoethionine under mammalian physiological conditions generating superoxide anion may possibly form a hydroxyl radical.
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Selenium methylation and toxicity mechanism of Selenocystine
YAKUGAKU ZASSHI, 1997Co-Authors: Yasuyoshi Sayato, Katsuhiko Nakamuro, Tatsuya HasegawaAbstract:Selenium is an essential trace element and a toxicant for animals. Selenocystine, a selenium-containing amino acid, is one of the chemical forms in which selenium exists in food. This review summarized recent studies on the toxicity mechanism of Selenocystine in experimental animals. Hepatotoxicity is caused by repeated oral administration of Selenocystine. Selenocystine is metabolized by reduced glutathione and/or glutathione reductase to hydrogen selenide via selenocysteine-glutathione selenenyl sulfide. The hydrogen selenide is a key intermediate in the selenium methylation metabolism of inorganic and organic selenium compounds. Accumulation of the hydrogen selenide resulting from inhibition of the selenium methylation metabolism, detoxification metabolic pathway of selenium, is found in animals following repeated administration of a toxic dose of Selenocystine. The excess of the hydrogen selenide produced by inhibition of the selenium methylation metabolism contributes to the hepatotoxicity caused by Selenocystine.
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Identification and metabolism of selenocysteine-glutathione selenenyl sulfide (CySeSG) in small intestine of mice orally exposed to Selenocystine
Archives of Toxicology, 1996Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Yasuyoshi SayatoAbstract:This investigation was carried out to elucidate the chemical form of selenium-containing metabolite in small intestine of ICR male mice orally administered Selenocystine (CySeSeCy). The metabolite in intestinal cytosol of mice treated with CySeSeCy (50 mg/kg) was identified as selenocysteine-glutathione selenenyl sulfide (CySeSG) by high performance liquid chromatography using a gel filtration and reversed phase column. Hydrogen selenide formation was caused as a result of the anaerobic reaction between the CySeSG and liver cytosol containing selenocysteine β-lyase, which specifically acts on selenocysteine (CySeH). Effects of GSH or glutathione reductase on hydrogen selenide formation from CySeSG reacted with the liver cytosol were examined. The CySeSG was nonenzymatically reduced to CySeH by excess GSH in the liver cytosol. It was also recognized that CySeSG was enzymatically reduced to CySeH by glutathione reductase in the presence of NADPH. These results indicate that the chemical form of this metabolite is CySeSG, which has a molecular weight of 473, the CySeSG is then reduced by excess GSH and/or gluta- thione reductase yielding CySeH, which is decomposed by selenocysteine β-lyase to hydrogen selenide. CySeSG may be a stable precursor of hydrogen selenide in animals.
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Chemical form of selenium-containing metabolite in small intestine and liver of mice following orally administered Selenocystine
Archives of Toxicology, 1995Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Makoto Mihara, Yasuyoshi SayatoAbstract:The chemical form of a selenium-containing metabolite in the small intestine following a single oral administration of Selenocystine was investigated with ICR male mice. Selenium content in the small intestine of animals treated with 50 mg/kg Selenocystine significantly increased 15 min, 1 h and 6 h after treatment. In contrast, Selenocystine significantly depressed the intestinal reduced glutathione (GSH) level at 1 h after administration. A significant negative correlation between the selenium level and the level of GSH in the small intestine was observed ( r =−0.83, p
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chemical form of selenium containing metabolite in small intestine and liver of mice following orally administered Selenocystine
Archives of Toxicology, 1995Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Makoto Mihara, Yasuyoshi SayatoAbstract:The chemical form of a selenium-containing metabolite in the small intestine following a single oral administration of Selenocystine was investigated with ICR male mice. Selenium content in the small intestine of animals treated with 50 mg/kg Selenocystine significantly increased 15 min, 1 h and 6 h after treatment. In contrast, Selenocystine significantly depressed the intestinal reduced glutathione (GSH) level at 1 h after administration. A significant negative correlation between the selenium level and the level of GSH in the small intestine was observed (r=−0.83, p<0.001). Analysis of the intestinal metabolite of Selenocystine showed that selenium-containing metabolites elute in two fractions from a Sephadex G-25 column: the low-molecular fraction (peak I) contained the Selenocystine, while the high-molecular fraction (peak II) contained selenocysteine-containing metabolite. An in vitro experiment was performed to gain insight into the mechanism for selenocysteine-containing metabolite production in the intestinal cytosol. When Selenocystine or selenocysteine reacted with excess GSH in the presence of intestinal homogenate, the peak II fraction which involved the selenocysteine-containing metabolite was recognized in the Sephadex G-25 chromatogram. From an examination of the distribution of the selenocysteine-containing metabolite, it was recognized that this metabolite exists in plasma and liver cytosol of mice after oral administration of Selenocystine. These results suggested that the mice treated with Selenocystine produce selenocysteine-containing metabolite by reaction of Selenocystine with excess GSH in the small intestine, and the metabolite is then transported to the liver through blood plasma.
Tomofumi Okuno - One of the best experts on this subject based on the ideXlab platform.
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Enhancement of Hydroxyl Radical Formation from Superoxide Anion Radical in the Presence of Organic Selenium Compounds
Journal of Health Science, 2001Co-Authors: Tomofumi Okuno, Hitoshi Ueno, Hitoshi Kawai, Tatsuya Hasegawa, Katsuhiko NakamuroAbstract:The generation of superoxide anion or hydroxyl radical derived from the organic selenium compounds selenomethionine, selenoethionine, Selenocystine, selenocystamine and selenocysteine-glutathione selenenyl sulfide (CySeSG) was investigated by the electron spin resonance (ESR) technique with 5, 5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trapping agent. The intensity of ESR signals of DMPO-OOH adduct formed by the reaction of the hypoxanthine/xanthine oxidase reaction system with DMPO decreased in the presence of selenomethionine or selenoethionine. However, the decrease of this ESR signal intensity was not due to superoxide anion-scavenging ability of these selenium compounds. When selenomethionine or selenoethionine existed in the superoxide anion generating system at a higher concentration, a new ESR signal was recognized. This signal disappeared with the addition of a hydroxyl radical-scavenging reagent and was similar to the signal of DMPO-OH adduct. The lack of structural change in selenomethionine or selenoethionine following reaction with components of the superoxide anion generating system suggested that these selenium compounds act as a catalyst. Such a phenomenon was not observed in the superoxide anion generating system in the presence of Selenocystine, selenocystamine or CySeSG. These findings suggested that coexistence of selenomethionine or selenoethionine under mammalian physiological conditions generating superoxide anion may possibly form a hydroxyl radical.
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Identification and metabolism of selenocysteine-glutathione selenenyl sulfide (CySeSG) in small intestine of mice orally exposed to Selenocystine
Archives of Toxicology, 1996Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Yasuyoshi SayatoAbstract:This investigation was carried out to elucidate the chemical form of selenium-containing metabolite in small intestine of ICR male mice orally administered Selenocystine (CySeSeCy). The metabolite in intestinal cytosol of mice treated with CySeSeCy (50 mg/kg) was identified as selenocysteine-glutathione selenenyl sulfide (CySeSG) by high performance liquid chromatography using a gel filtration and reversed phase column. Hydrogen selenide formation was caused as a result of the anaerobic reaction between the CySeSG and liver cytosol containing selenocysteine β-lyase, which specifically acts on selenocysteine (CySeH). Effects of GSH or glutathione reductase on hydrogen selenide formation from CySeSG reacted with the liver cytosol were examined. The CySeSG was nonenzymatically reduced to CySeH by excess GSH in the liver cytosol. It was also recognized that CySeSG was enzymatically reduced to CySeH by glutathione reductase in the presence of NADPH. These results indicate that the chemical form of this metabolite is CySeSG, which has a molecular weight of 473, the CySeSG is then reduced by excess GSH and/or gluta- thione reductase yielding CySeH, which is decomposed by selenocysteine β-lyase to hydrogen selenide. CySeSG may be a stable precursor of hydrogen selenide in animals.
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Chemical form of selenium-containing metabolite in small intestine and liver of mice following orally administered Selenocystine
Archives of Toxicology, 1995Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Makoto Mihara, Yasuyoshi SayatoAbstract:The chemical form of a selenium-containing metabolite in the small intestine following a single oral administration of Selenocystine was investigated with ICR male mice. Selenium content in the small intestine of animals treated with 50 mg/kg Selenocystine significantly increased 15 min, 1 h and 6 h after treatment. In contrast, Selenocystine significantly depressed the intestinal reduced glutathione (GSH) level at 1 h after administration. A significant negative correlation between the selenium level and the level of GSH in the small intestine was observed ( r =−0.83, p
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chemical form of selenium containing metabolite in small intestine and liver of mice following orally administered Selenocystine
Archives of Toxicology, 1995Co-Authors: Tatsuya Hasegawa, Tomofumi Okuno, Katsuhiko Nakamuro, Makoto Mihara, Yasuyoshi SayatoAbstract:The chemical form of a selenium-containing metabolite in the small intestine following a single oral administration of Selenocystine was investigated with ICR male mice. Selenium content in the small intestine of animals treated with 50 mg/kg Selenocystine significantly increased 15 min, 1 h and 6 h after treatment. In contrast, Selenocystine significantly depressed the intestinal reduced glutathione (GSH) level at 1 h after administration. A significant negative correlation between the selenium level and the level of GSH in the small intestine was observed (r=−0.83, p<0.001). Analysis of the intestinal metabolite of Selenocystine showed that selenium-containing metabolites elute in two fractions from a Sephadex G-25 column: the low-molecular fraction (peak I) contained the Selenocystine, while the high-molecular fraction (peak II) contained selenocysteine-containing metabolite. An in vitro experiment was performed to gain insight into the mechanism for selenocysteine-containing metabolite production in the intestinal cytosol. When Selenocystine or selenocysteine reacted with excess GSH in the presence of intestinal homogenate, the peak II fraction which involved the selenocysteine-containing metabolite was recognized in the Sephadex G-25 chromatogram. From an examination of the distribution of the selenocysteine-containing metabolite, it was recognized that this metabolite exists in plasma and liver cytosol of mice after oral administration of Selenocystine. These results suggested that the mice treated with Selenocystine produce selenocysteine-containing metabolite by reaction of Selenocystine with excess GSH in the small intestine, and the metabolite is then transported to the liver through blood plasma.
Ludger A Wessjohann - One of the best experts on this subject based on the ideXlab platform.
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straightforward method for the synthesis of selenocysteine and Selenocystine derivatives from l serine methyl ester
ChemInform, 2011Co-Authors: Antonio L. Braga, Ludger A Wessjohann, Paulo Sérgio Taube, Fabio Z. Galetto, Fabiano Molinos De AndradeAbstract:O-Mesylated L-serine methyl ester, generated in situ, reacts with selenolate anions in a one-pot manner to yield various target compounds.
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Straightforward Method for theSynthesis of Selenocysteine and Selenocystine Derivatives from l-Serine Methyl Ester
Synthesis, 2010Co-Authors: Antonio L. Braga, Ludger A Wessjohann, Paulo Sérgio Taube, Fabio Z. Galetto, Fabiano Molinos De AndradeAbstract:A set of selenoamino acids has been efficiently synthesized under smooth conditions by a simple, flexible and modular strategy. In this method, O-mesylated L -serine methyl ester is generated in situ and directly substituted with various selenolate anions to afford selenocysteine, selenolanthionine, and Selenocystine derivatives in good yields. Also, a tellurocysteine derivative can be obtained by this method.
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one pot synthesis of selenocysteine containing peptoid libraries by ugi multicomponent reactions in water
Chemical Communications, 2006Co-Authors: Muhammad Abbas, John Bethke, Ludger A WessjohannAbstract:Selenocysteine containing peptoids and peptide–peptoid conjugates were synthesized by combinatorial Ugi-MCRs (multicomponent reactions) in water: for the first time, an acetal (selenoacetal 2a) was used in Ugi-MCR to furnish selenocysteine peptoids in one step as model compounds for selenocysteine peptides and proteins.
