title: Metabolism of benzo[a]pyrene in the combined rat liver--lung perfusion system.
abstract: The influence of the insertion of a liver into the perfusion circuit of a lung on the availability of benzo[a]pyrene and benzo[a]pyrene metabolites to the lung was examined. Perfused lungs from 5,6-benzoflavone pretreated rats release high quantities of free benzo[a]pyrene metabolites and conjugates into the perfusion medium. The insertion of a liver taken from an untreated rat reduces the concentration of unmetabolized substrate and of free diol, quinone and phenol metabolites to less than 20% of the concentrations found in the absence of the liver. When the liver of a 5,6-benzoflavone-pretreated rat is used, substrate depletion is not much greater than in the experiments with control livers; however, the concentration of free metabolites is further reduced to one third. In lung tissue, only very low levels of benzo[a]pyrene and greatly reduced levels of free and conjugated metabolites are found when a 5,6-benzoflavone-induced liver had been present during perfusion. These findings can explain the protective effect of the liver on covalent binding of benzo[a]pyrene metabolites to pulmonary macro-molecules observed in previous experiments with the combined liver-lung perfusion model [Klaus et al., Biochem. Biophys. Res. Commun., 105 (1982) 596].
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene / Q000378:metabolism*; D001571:Benzoflavones / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D004347:Drug Interactions; D007274:Injections, Intraperitoneal; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008168:Lung / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution; D019324:beta-Naphthoflavone
chemical_list: D001571:Benzoflavones; D001564:Benzo(a)pyrene; D019324:beta-Naphthoflavone