Qualitative effects of dioxin on molars vary among inbred mouse strains

Objective luated the effects of different levels of the potent environmental toxicant and teratogen, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), on molar development in mice in six inbred strains, all with TCDD responsive Ahr alleles. nt females were exposed on gestation day 13 to 4 different levels of TCDD (control, 0.01, 0.1 and 1.0 μg/kg) and their offspring were examined for the frequency of missing third molars (M3s) and for differences in first mandibular molar (M1) cuspal morphology. s g M3s were prevalent only in mice in two strains, C3H/HeJ and CBA/J, and their frequency significantly increased with increasing TCDD exposure. The frequency of the M1 variant was high in mice in only one strain, C57BL/10J, and was significantly higher in the treated compared with the control group. sions mice strains exhibited differential responses to TCDD suggesting that there is a genetic component, beyond Ahr differences, mediating the effects of TCDD on molar development.