Cleft palates and liver weight data of two different mixtures of PCDDs in pregnant mice related to organ dosage

Abstract

Three doses of two different mixtures of PCDD homologues and congeners were administered on day 9 of pregnancy to C57BL/6J (B6) or DBA/2J (D2) mice. Doses given to D2 mice were tenfold higher than those given to B6 mice. In addition, 2,3,7,8-TCDD (15 μg/kg and 150 μg/kg b.w. resp.) was tested separately as well as in combination with the applied doses of the PCDD mixtures. On day 18 of pregnancy the mice were sacrificed, organ weight data were taken, and the number of fetuses with cleft palates was determined. Liver weight was significantly increased in all treated D2 mice, however, in B6 mice only when 2,3,7,8-TCDD was co-administered. The incidence of cleft palates were dose-dependent in the fetuses of D2 mice. In B6 mice this malformation occured either after the administration of 2,3,7,8-TCDD alone or with 2,3,7,8-TCDD added to the different PCDD mixtures. The concentration of the 2,3,7,8-substituted PCDDs analysed in the liver and white adipose tissue reflect the doses and the kind of mixture given orally. However, in the liver of B6 mice, organ dosages (expressed as I-TEQ) obviously do not correspond to the administered increasing dosages. It is concluded that there is some additive effect for TCDD and the 2,3,7,8-substituted congeners.