title: DNA alterations and enzyme activities in Japanese medaka (Oryzias latipes) exposed to diethylnitrosamine.
abstract: Several molecular and biochemical markers of genotoxicity were adapted for measurement in the medaka, and were used to describe the effects of treatment of the organism with diethylnitrosamine (DEN). DEN treatment inhibited the activity of a detoxication enzyme activity (ethoxyresorufin-O-deethylase) and increased the activity of glutathione-S-transferase. This pattern of response has been described in preneoplastic rodent cells. No O6-ethyl guanine adducts were detected, and a slight, but statistically significant, increase in DNA strand breaks was observed. These results are consistent with the hypothesis that prolonged exposure to high levels of DEN induced alkyltransferase activity which enzymatically removes any O6-ethyl guanine adducts but does not result in strand breaks or hypomethylation of the DNA such as might be expected from excision repair of chemically modified DNA.
authors.affiliation: Environmental Sciences Division, Oak Ridge National Laboratory, TN 37831-6036.
authors.forename: J F
authors.initials: JF
authors.lastname: McCarthy
authors.forename: H
authors.initials: H
authors.lastname: Gardner
authors.forename: M J
authors.initials: MJ
authors.lastname: Wolfe
authors.forename: L R
authors.initials: LR
authors.lastname: Shugart
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D019363:Cytochrome P-450 CYP1A1; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004247:DNA / Q000187:drug effects* / Q000378:metabolism; D004249:DNA Damage; D004052:Diethylnitrosamine / Q000633:toxicity*; D004798:Enzymes / Q000378:metabolism*; D005434:Flow Cytometry; D005982:Glutathione Transferase / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism; D009990:Oryzias / Q000502:physiology*; D010088:Oxidoreductases / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D004798:Enzymes; D004052:Diethylnitrosamine; D004247:DNA; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1; D005982:Glutathione Transferase