FXR expression and activity do not decrease during pregnancy. Liver tissues of Tg-CYP2D6 mice were collected at pre-pregnancy (Virgin), 17 days of pregnancy (G17), and 7 days postpartum (PP7). A, mRNA expression was determined by qRT-PCR (n = 4, mean ± S.D.). B, FXR recruitment to Shp promoter was analyzed by a ChIP assay (n = 4, mean ± S.D.; *, p < 0.05, one-way ANOVA versus virgin).