title: Induction of unscheduled DNA synthesis in suspensions of rat hepatocytes by an environmental toxicant, 3,3'4,4'-tetrachloroazobenzene.
abstract: Unscheduled DNA synthesis was induced by 3,3'4,4'-tetrachloroazobenzene (TCAB)) in freshly isolated suspensions of rat hepatocytes. A dose-dependent response was demonstrated. Hepatocellular DNA was obtained after the chloroform-isoamyl alchohol-phenol extraction of the isolated nuclei. The induction of unscheduled DNA synthesis was measured by the incorporation of [3H]-thymidine in the presence of hydroxyurea as determined by the scintillation counting assay. DNA repair data obtained in this study on benzo[a]pyrene and methyl methanesulfonate are comparable to a previous report using primary cultures of hepatocytes and cesium chloride gradients. Hence, the present method offers promise as a rapid and sensitive screen for chemical carcinogens.
mesh_terms: D000818:Animals; D001391:Azo Compounds / Q000494:pharmacology*; D001580:Benzopyrenes / Q000494:pharmacology; D002273:Carcinogens; D002722:Chlorobenzenes / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis*; D004260:DNA Repair / Q000187:drug effects*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D051381:Rats
chemical_list: D001391:Azo Compounds; D001580:Benzopyrenes; D002273:Carcinogens; D002722:Chlorobenzenes; C013279:3,4,3',4'-tetrachloroazobenzene; D004247:DNA; D008741:Methyl Methanesulfonate