TOXICOKINETIC MIXTURE INTERACTIONS BETWEEN CHLORINATED AROMATIC-HYDROCARBONS IN THE LIVER OF THE C57BL 6J MOUSE .2. POLYCHLORINATED DIBENZO-P-DIOXINS (PCDDS), DIBENZOFURANS (PCDFS) AND BIPHENYLS (PCBS)/

Six groups of C57BL/6J mice received single oral doses of 1.5-10.6 nmo l/kg 1,2,3,7,8-pentachlorodibeno-p-dioxin (PnCDD), 1,2,3,6,7,8-hexachl orodibenzo-p-dioxin (HxCDD) or 2,3,4,7,8-pentacholorodibenzofuran (PnC DF) as single compounds or in combination with 300 mumol/kg 2,2',4,4', 5,5'-hexachlorobiphenyl (HxCB). Two other groups of mice received a mi xture of the first three compounds, either with or without HxCB. The h epatic deposition and elimination of the compounds and their CYP1a dep endent 7-ethoxyresorufin-O-deethylation (EROD) activity were studied u ntil day 175. Interactive effects on the hepatic deposition of PnCDD w ere observed in most of the mixed dose groups. For HxCDD and PnCDF int eractive effects were either very small or absent. No interactive effe cts were observed on hepatic elimination rates of PnCDD, HxCDD or PnCD F. No evidence was found for the influence of HxCB cotreatment on the hepatic concentration-response curves of the three compounds or their mixture. Based on the results from the present study it is concluded t hat PCDDs, PCDFs and PCBs may influence each other's, toxicokinetics w hen administered in mixtures.