FIG. 4. Effects of maternal exposure to TCDD on the fetal expression of mRNAs coding proteins involved in steroidogenesis and ligand binding (A) and on fetal testicular CYP17 activity (B). Testes and adrenals (Adr.) were removed from fetuses of dams (GD20) that were pretreated with TCDD at GD15. Although only representative results are shown (A), statistical differences in the TCDD-induced alteration described in the text were confirmed by using six fetuses, two of which were removed from three different parents. C, Control; T, TCDD. In experiment B, pooled testis homogenate from six fetuses, two of which were removed from three different dams, was used as the enzyme source. 17-OH-Progesterone, 17-Hydroxyprogesterone.