title: Comparative genotoxicity studies of the flame retardant tris(2,3-dibromopropyl)phosphate and possible metabolites.
abstract: Tris(2,3-dibromopropyl)phosphate (Tris-BP) was activated to mutagens in the Salmonella/microsome quantitative test system. Liver microsomes from rats pretreated with phenobarbital (PB) increased the mutagenicity of 0.05 mM Tris-BP to 186% of the activity obtained with liver microsomes from untreated rats. The addition of 0.02 mM Tris-BP to V79 Chinese hamster cells co-incubated with liver microsomes from PB-pretreated rats increased the number of mutants by a factor of 9.7. Tris-BP also caused genotoxic and cytotoxic responses in primary monolayers of rat hepatocytes. The relative increase in unscheduled DNA synthesis after treatment with 0.05 mM Tris-BP was 2.3-fold as measured by scintillation counting of radiolabelled thymidine incorporated into DNA of isolated nuclei. The use of hepatocytes isolated from PB-pretreated rats reduced the increases in DNA repair synthesis relatively to that in control cells. Monolayers of hepatocytes from untreated rats co-cultured with Salmonella typhimurium TA100 activated Tris-BP to mutagenic intermediates which were released into the culture medium. The studies with the V79 and liver-cell systems indicate that the reactive intermediates formed from Tris-BP are sufficiently stable and lipophilic to traverse the various membranes from the site of generation to the respective cellular targets. The relative degree of genotoxic responses of bis(2,3-dibromopropyl)phosphate, 2,3-dibromopropylphosphate, tris(2,3-bromopropyl)phosphate, tris(2-bromopropyl)phosphate and 2,3-dibromopropanol in the systems studied did not indicate that these compounds were proximate or ultimate reactive metabolites of Tris-BP in liver-derived activation systems.
mesh_terms: D000818:Animals; D001711:Biotransformation; D002460:Cell Line; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004260:DNA Repair; D004261:DNA Replication / Q000187:drug effects; D005411:Flame Retardants / Q000633:toxicity*; D008168:Lung; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D009152:Mutagenicity Tests; D009153:Mutagens; D009154:Mutation; D010755:Organophosphates / Q000633:toxicity*; D009943:Organophosphorus Compounds / Q000633:toxicity*; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship
chemical_list: D005411:Flame Retardants; D009153:Mutagens; D010755:Organophosphates; D009943:Organophosphorus Compounds; C012085:tris(2,3-dibromopropyl)phosphate