Downregulation of BA biosynthesis is not caused by the activation of FXR in 2c70KO and DKO mice. Serum, liver, and terminal ileum were collected from 44 mice (n = 6, 7, 4, 10, 5, 4, 4, and 4 for male WT, 2a12KO, 2c70KO, DKO, female WT, 2a12KO, 2c70KO, and DKO, respectively) at 11.1 ± 0.8 (mean ± SD) weeks of age. RNA was extracted from the liver and the terminal ileum. A: Hepatic mRNA expression levels of Fxr and related genes. B: Hepatic mRNA expression levels of Pxr and related genes. C: Hepatic mRNA expression levels of Lxra and related genes. D: Hepatic mRNA expression levels of Ppara and a related genes. E: Serum concentrations of FGF15 and mRNA expression levels of Fxr and related genes in the terminal ileum. mRNA expression levels were standardized to those of Gapdh, and the mean expression levels in male WT mice were set to 1.0. Each column and error bar represents the mean and SEM. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001 were considered significantly different by the Tukey-Kramer test.