Induction of hepatic CYP1A activity as a biomarker for environmental exposure to Aroclor 1254 in feral rodents.
Specimens of the feral mouse species Reithrodontomys fulvescens trapped from a polychlorinated biphenyl (PCB)-contaminated field location had hepatic ethoxyresorufin (ETR) O-dealkylase activities and immunoreactive CYP1A protein contents which were two- to threefold higher than those measured in animals of the same species and sex collected from non PCB-contaminated reference sites. Specimens with hepatic ETR O-dealkylase activities differing by as little as 50% could readily be assigned as originating from the PCB or reference sites by the use of a specific chemical inhibitor of cytochrome P450IA (CYP1A). The relative levels of ETR O-dealkylase activity in R. fulvescens significantly correlated with hepatic PCB burdens (r = 0.819, P less than 0.01). When the magnitudes of the induced ETR O-dealkylase activities corresponding to given hepatic PCB burdens were compared between the feral animals, F344/NCr rats (Rattus norvegicus) or B6C3F1 mice (Mus musculus) exposed in the laboratory to dietary Aroclor 1254, the order of sensitivity to the inducing effects of PCBs were F344/NCr rat greater than B6C3F1 mouse greater than R. fulvescens.
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Laboratory of Comparative Carcinogenesis, National Cancer Institute, PRI-DynCorp, Frederick Cancer Research and Development Center, Maryland 21702-1201.
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D000818:Animals; D001140:Aroclors / Q000633:toxicity*; D015415:Biomarkers; D001822:Body Burden; D002273:Carcinogens / Q000633:toxicity*; D020111:Chlorodiphenyl (54% Chlorine); D019363:Cytochrome P-450 CYP1A1; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis*; D004781:Environmental Exposure; D005260:Female; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D051379:Mice; D010088:Oxidoreductases / Q000096:biosynthesis*; D011078:Polychlorinated Biphenyls / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013045:Species Specificity
D001140:Aroclors; D015415:Biomarkers; D002273:Carcinogens; D020111:Chlorodiphenyl (54% Chlorine); D003577:Cytochrome P-450 Enzyme System; D011078:Polychlorinated Biphenyls; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1