Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Effects of Age, Species Difference, Antibiotics and Toxicants on Intestinal Enzyme Activity and Genotoxicity.
Author Chadwick, R. W. ; George, S. E. ; Chang, J. ; Kohan, M. J. ; Dekker, J. P. ;
CORP Author Health Effects Research Lab., Research Triangle Park, NC. ;North Carolina Univ. at Chapel Hill. ;Environmental Health Research and Testing, Inc., Research Triangle Park, NC.
Publisher 1993
Year Published 1993
Report Number EPA/600/J-94/021;
Stock Number PB94-137338
Additional Subjects Mutagens ; Intestines ; Antibiotics ; Toxic substances ; Enzymes ; Aging(Physiology) ; Species diversity ; Metabolic activation ; Gas chromatography ; Environmental carcinogens ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB94-137338 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. 05/14/1994
Collation 16p
Altered intestinal enzyme activity significantly affects the biotransformation and toxicity of many xenobiotics. This article summarizes research that employs a novel gas-liquid chromatographic assay to investigate the effects of age, species difference, antibiotics, and environmental chemicals on enzyme activity in various regions of the intestinal tract. Significant research findings include the following: (a) age-dependent alterations in enzyme activity in the gastrointestinal (GI) tract of the developing animal that suggest a changing susceptibility to toxicants during this period; (b) discovery of previously unreported mucosal enzymes in the small intestine that are present in germ-free rats and are not susceptible to antibiotics; (c) markedly greater intestinal nitroreductase activity and significantly higher bioactivation of the procarcinogen 2,6-dinitrotoluene (DNT) in CD-1 mice than in Fischer 344 rats; (d) significantly altered intestinal enzyme activity in rats pretreated with lindane, pentachlorophenol, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), or Aroclor 1254; (e) potentiated DNT genotoxicity by Aroclor 1254 and pentachlorophenol pretreatment; and (f) a transient antagonism of DNT genotoxicity by 2,4,5-T pretreatment. Enzyme activity in the small intestine may have greater toxicological importance than previously thought in the biotransformation of environmental chemicals and as an indicator of change in the microbial flora.