In utero TCDD exposure increases Cyp1b1 mRNA abundance in ventral UGM but does not alter Fgf10 mRNA abundance or distribution in this region. Male fetal mice were exposed in utero to corn oil (vehicle) or TCDD (5 μg/kg maternal dose) on E15.5. (A) Cyp1b1 and Fgf10 mRNA abundance was determined by real-time RT-PCR on E16.5 and normalized to Ppia mRNA abundance. Results are mean ± SE of n ≥ 3 independent samples per group from at least three separate litters. Significant differences between groups (p < 0.05) are indicated by an asterisk. (B) ISH was used to visualize the pattern of AHR-responsive Cyp1b1 mRNA expression and Fgf10 expression in sagittal UGS sections on E16.5. Dashed lines were added to demarcate the boundary between UGE and UGM, thin gray lines were added to show the outside edge of each UGS section, and a thin black oval indicates the approximate position of the VMP. BL. bladder; E, UGE; M, UGM; and PU, pelvic urethra.