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Effects of age, species difference, antibiotics and toxicants on intestinal enzyme activity and genotoxicity

Journal Article · · Environmental Toxicology and Chemistry; (United States)
; ; ;  [1]; ; ;  [2]; ;  [3]
  1. Environmental Protection Agency, Research Triangle Park, NC (United States). Health Effects Research Lab.
  2. Univ. of North Carolina, Chapel Hill, NC (United States)
  3. Environmental Health Research and Testing Inc., Research Triangle Park, NC (United States)
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Altered intestinal enzyme activity significantly affects the biotransformation and toxicity of many xenobiotics. This article summarizes research, supported by the US Air Force Bioenvironmental Hazards Research Program, 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.

OSTI ID:
7264894
Journal Information:
Environmental Toxicology and Chemistry; (United States), Journal Name: Environmental Toxicology and Chemistry; (United States) Vol. 12:8; ISSN 0730-7268; ISSN ETOCDK
Country of Publication:
United States
Language:
English

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Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ABSORPTION
AROMATICS
BIOLOGICAL EFFECTS
CHLORINATED AROMATIC HYDROCARBONS
ENZYME ACTIVITY
ENZYMES
GENETIC EFFECTS
HALOGENATED AROMATIC HYDROCARBONS
INTESTINAL ABSORPTION
METABOLISM
NITRO COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDOREDUCTASES
POLYCHLORINATED BIPHENYLS
PROTEINS
SORPTION
TOXICITY
UPTAKE
XENOBIOTICS