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LIMITED PCB ANTAGONISM OF TCDD-INDUCED MALFORMATIONS IN MICE
Citation:
Morrissey, R., M. Harris, J. Diliberto, AND L. Birnbaum. LIMITED PCB ANTAGONISM OF TCDD-INDUCED MALFORMATIONS IN MICE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/142 (NTIS PB92166768).
Description:
C57BL/6N mice, used to model induction of cleft palate and kidney malformations in offspring following maternal treatment with TCDD, were dosed on gestation day (gd) 9 with ,2',4,4',5,5'-hexachloro-biphenyl (HCB) (62.5, 125, 250, 500. 1000 mg/kg) and/or gd 10 with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (15 or 18 ug/kg) to investigate the potential protective effects of HCB against TCDD- nduced teratogenicity. aternal body weight gain was increased by combinations of 15 ug TCDD/kg and 125-500 mg HCB/kg and decreased at doses of 15 ug TCDD/kg + 1000 KGB mg/kg. t the doses used in this study, there was no effect of either compound on number of live or dead offspring. etal body weight was slightly decreased in all groups dosed with 250 mg KGB/kg. CB did not induce cleft palate at a dose of 1000 mg/kg, but did induce increases in hydronephrosis and hydroureter at 500 and 1000 mg/kg. ombinations of HCB and TCDD decreased the incidence of cleft palate induced by TCDD alone, but only at doses of 15 ug TCDD/kg combined with 125-500 mg HCB/kg. he window for antagonism of hydronephrosis (incidence and severity) appeared narrower (15 ug TCDD/kg + 500 mg HCB/kg). CB induced increases (3 fold) in EROD activity at doses of 500 and 1000 mg/kg, suggesting that the limited antagonism of TCDD teratogenicity by CB would be consistent with control by Ah receptor.