title: Protooncogene expression in rat liver by polychlorinated biphenyls (PCB).
abstract: 1. The expression of 10 protooncogenes was studied in control rat liver and at various times after exposure to polychlorinated biphenyls (PCB), a known tumour promoter. 2. The expression of protooncogenes in liver is more pronounced in those rats treated with PCB beginning at weaning ('weanlings') than in adult rats. 3. The RNA levels of c-Ha-ras, c-raf, c-yes, c-erbA and c-erbB are elevated after PCB feeding. 4. Nuclear run-on transcription analysis revealed that the altered expression of the protooncogenes is transcriptionally regulated. 5. In one group the prompt rise of the protooncogene transcription rate is followed by a decline (c-Ha-ras, c-raf c-yes). In a second group a further increase in transcription at later feeding times (c-erbA, c-erbB) was observed. 6. A correlation between the altered expression of these protooncogenes and the action of PCB as a tumour promotor remains to be determined.
authors.affiliation: Gesellschaft für Strahlen- und Umweltforschung, Abteilung für Zellchemie, Neuherberg, Germany.
authors.forename: H S
authors.initials: HS
authors.lastname: Jenke
authors.forename: G
authors.initials: G
authors.lastname: Michel
authors.forename: S
authors.initials: S
authors.lastname: Hornhardt
authors.forename: J
authors.initials: J
authors.lastname: Berndt
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D015152:Blotting, Northern; D002273:Carcinogens / Q000633:toxicity; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D015342:DNA Probes; D004032:Diet; D004052:Diethylnitrosamine / Q000633:toxicity; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D015151:Immunoblotting; D008099:Liver / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*; D010957:Plasmids / Q000187:drug effects; D011078:Polychlorinated Biphenyls / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism; D011519:Proto-Oncogenes / Q000187:drug effects*; D012334:RNA, Neoplasm / Q000032:analysis / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains; D014158:Transcription, Genetic
chemical_list: D002273:Carcinogens; D015342:DNA Probes; D012334:RNA, Neoplasm; D004052:Diethylnitrosamine; D011078:Polychlorinated Biphenyls; D011493:Protein Kinase C