title: Effect of varying the length of exposure to polybrominated biphenyls on the development of gamma-glutamyl transpeptidase enzyme-altered foci.
abstract: Female Sprague-Dawley rats were fed polybrominated biphenyls (PBBs) for 15 or 140 days after a 70% partial hepatectomy and diethylnitrosamine administration (10 mg/kg body weight) to determine the effect of varying the length of exposure to PBBs on the enhancement of gamma-glutamyl transpeptidase enzyme-altered foci. fireMaster BP-6R, a commercial mixture of PBBs, was fed to rats at a dietary concentration of 100 mg/kg for 15 days or 10 mg/kg for 140 days during the promotion phase of a two-stage hepatocarcinogenesis assay. Results indicate that short term exposure to PBBs is as effective as long term exposure in enhancing the development of enzyme-altered foci.
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced*; D008862:Microsomes, Liver / Q000201:enzymology; D011075:Polybrominated Biphenyls / Q000008:administration & dosage*; D051381:Rats; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
chemical_list: D011075:Polybrominated Biphenyls; D005723:gamma-Glutamyltransferase