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SOME EFFECTS OF AGE, SPECIES DIFFERENCE, ANTIBIOTICS AND TOXICANT EXPOSURE ON INTESTINAL ENZYME ACTIVITY AND GENOTOXICITY
Citation:
Chadwick, R., S. George, J. Chang, M. Kohan, J. Dekker, J. Allison, J. Long, M. Duffy, AND L. Forehand. SOME EFFECTS OF AGE, SPECIES DIFFERENCE, ANTIBIOTICS AND TOXICANT EXPOSURE ON INTESTINAL ENZYME ACTIVITY AND GENOTOXICITY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/021 (NTIS PB94137338).
Description:
Altered intestinal enzyme activity significantly affects the biotransformation and toxicity of many xenobiotics. his review summarizes research, supported by the Air Force Bioenvironmental Hazards Research Program, that employs a novel gas-liquid chromatographic assay to investigate the effect of age, species difference, antibiotics, and environmental chemicals on enzyme activity in various regions of the intestinal tract. ignificant research findings include the following: (1) Age-dependent alterations in enzyme activity in the G.I. tract of the developing animal suggest a changing susceptibility to toxicants during this period, (2) Discovery of previously unreported mucosal enzymes in the small intestine that are present in germfree rats and that are not susceptible to antibiotics, (3) 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, (4) Significantly altered intestinal enzyme activity in rats pretreated with lindane, pentachlorophenol,i 2,.4,5-T, or Aroclor 1254, (5) Potentiated DNT genotoxicity by Aroclor 1254 and pentachlorophenol pretreatment, and (6) A transient antagonism of DNT genotoxicity by 2,4,5-T pretreatment. nzyme 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.