Toxicological Sciences 54, 52-59 (2000)
Copyright © 2000 by the Society of Toxicology
Glutathione S-Transferase in Mucus of Rat Small Intestine
,1
* Department of Biochemistry, and
Graduate Program in Pharmacology and Physiology, Emory University, Atlanta, Georgia
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.
Key Words: glutathione; 1-chloro-2,4-dinitrobenzene; conjugation; electrophiles; diet.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
J. J. Salmen, F. Skufca, A. Matt, G. Gushansky, A. Mason, and C. S. Gardiner Role of Glutathione in Reproductive Tract Secretions on Mouse Preimplantation Embryo Development Biol Reprod, August 1, 2005; 73(2): 308 - 314. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. He, K. Openo, M. McCullough, and D. P. Jones Total Equivalent of Reactive Chemicals in 142 Human Food Items Is Highly Variable Within and Between Major Food Groups J. Nutr., May 1, 2004; 134(5): 1114 - 1119. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Petri, C. Tannergren, B. Holst, F. A. Mellon, Y. Bao, G. W. Plumb, J. Bacon, K. A. O'Leary, P. A. Kroon, L. Knutson, et al. ABSORPTION/METABOLISM OF SULFORAPHANE AND QUERCETIN, AND REGULATION OF PHASE II ENZYMES, IN HUMAN JEJUNUM IN VIVO Drug Metab. Dispos., June 1, 2003; 31(6): 805 - 813. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. P. Basten, Y. Bao, and G. Williamson Sulforaphane and its glutathione conjugate but not sulforaphane nitrile induce UDP-glucuronosyl transferase (UGT1A1) and glutathione transferase (GSTA1) in cultured cells Carcinogenesis, August 1, 2002; 23(8): 1399 - 1404. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. J. Dahm and D. P. Jones Rat Jejunum Controls Luminal Thiol-Disulfide Redox J. Nutr., November 1, 2000; 130(11): 2739 - 2745. [Abstract] [Full Text] [PDF] |
||||
![]() |
A B DeAngelo Response to "Epigenetic mechanisms of chemical carcinogenesis" by James E. Klaunig, Lisa M. Kamendulis, and Xu Yong Human and Experimental Toxicology, October 1, 2000; 19(10): 561 - 562. [PDF] |
||||




