Glutathione S-Transferase in Mucus of Rat Small Intestine.

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Title: Glutathione S-Transferase in Mucus of Rat Small Intestine.
Authors: Samiec, P. S.1,2, Dahm, L. J.1, Jones, D. P.1 dpjones@emory.edu
Source: Toxicological Sciences. Mar2000, Vol. 54 Issue 1, p52-59. 8p. 1 Diagram, 9 Graphs.
Subjects: Glutathione, Electrophiles, Benzene, Small intestine, Mucus
Abstract: Glutathione S-transferases in the small intestine function in detoxification of electrophilic compounds ingested in foods, dietary supplements, and orally administered drug preparations. Although the required substrate glutathione (GSH) is synthesized in the intestinal enterocytes, the rate of synthesis is slow compared to both the maximal GST activity and the rate of uptake of luminal GSH. GSH is supplied to the intestinal lumen in the bile, and normal luminal concentrations in the rat are about 250 μM. The present study was designed to test the hypothesis that exogenous GSH is used for intestinal conjugation by glutathione S-transferase. The results show that 250 μM of extracellular GSH stimulated conjugation of 1-chloro-2,4-dinitrobenzene by approximately 300% in rat intestinal enterocyte preparations. However, an unexpected finding was that most of this stimulated activity did not depend upon uptake of GSH by the enterocytes but was due to glutathione S-transferase associated with mucus. Immunohistochemistry of glutathione S-transferase in the intact small intestine confirmed that a portion of the GST is present in the mucus layer. The presence of this detoxication enzyme in the extracellular mucus layer provides a novel mechanism for preventing direct contact of potentially toxic dietary electrophiles with the intestinal enterocytes. [ABSTRACT FROM PUBLISHER]
Copyright of Toxicological Sciences is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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  Data: Glutathione S-Transferase in Mucus of Rat Small Intestine.
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  Data: <searchLink fieldCode="AR" term="%22Samiec%2C+P%2E+S%2E%22">Samiec, P. S.</searchLink><relatesTo>1,2</relatesTo><br /><searchLink fieldCode="AR" term="%22Dahm%2C+L%2E+J%2E%22">Dahm, L. J.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Jones%2C+D%2E+P%2E%22">Jones, D. P.</searchLink><relatesTo>1</relatesTo><i> dpjones@emory.edu</i>
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  Data: <searchLink fieldCode="JN" term="%22Toxicological+Sciences%22">Toxicological Sciences</searchLink>. Mar2000, Vol. 54 Issue 1, p52-59. 8p. 1 Diagram, 9 Graphs.
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  Data: <searchLink fieldCode="DE" term="%22Glutathione%22">Glutathione</searchLink><br /><searchLink fieldCode="DE" term="%22Electrophiles%22">Electrophiles</searchLink><br /><searchLink fieldCode="DE" term="%22Benzene%22">Benzene</searchLink><br /><searchLink fieldCode="DE" term="%22Small+intestine%22">Small intestine</searchLink><br /><searchLink fieldCode="DE" term="%22Mucus%22">Mucus</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Glutathione S-transferases in the small intestine function in detoxification of electrophilic compounds ingested in foods, dietary supplements, and orally administered drug preparations. Although the required substrate glutathione (GSH) is synthesized in the intestinal enterocytes, the rate of synthesis is slow compared to both the maximal GST activity and the rate of uptake of luminal GSH. GSH is supplied to the intestinal lumen in the bile, and normal luminal concentrations in the rat are about 250 μM. The present study was designed to test the hypothesis that exogenous GSH is used for intestinal conjugation by glutathione S-transferase. The results show that 250 μM of extracellular GSH stimulated conjugation of 1-chloro-2,4-dinitrobenzene by approximately 300% in rat intestinal enterocyte preparations. However, an unexpected finding was that most of this stimulated activity did not depend upon uptake of GSH by the enterocytes but was due to glutathione S-transferase associated with mucus. Immunohistochemistry of glutathione S-transferase in the intact small intestine confirmed that a portion of the GST is present in the mucus layer. The presence of this detoxication enzyme in the extracellular mucus layer provides a novel mechanism for preventing direct contact of potentially toxic dietary electrophiles with the intestinal enterocytes. [ABSTRACT FROM PUBLISHER]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Toxicological Sciences is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
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      – Type: doi
        Value: 10.1093/toxsci/54.1.52
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      – Code: eng
        Text: English
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        PageCount: 8
        StartPage: 52
    Subjects:
      – SubjectFull: Glutathione
        Type: general
      – SubjectFull: Electrophiles
        Type: general
      – SubjectFull: Benzene
        Type: general
      – SubjectFull: Small intestine
        Type: general
      – SubjectFull: Mucus
        Type: general
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      – TitleFull: Glutathione S-Transferase in Mucus of Rat Small Intestine.
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              Text: Mar2000
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              Y: 2000
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