Key mediators of bile acids (BA) synthesis in the liver of mice.

<p>A) Transcription factors p53 and farnesoid X receptor (FXR) can activate the transcription of small heterodimer partner (SHP) which inhibits 7-α-hydroxylase (Cyp7A1), the first enzyme in the BA synthesis pathway. Liver X receptor (LXR) can activate transcriptionally Cyp7A1 to produce more BA. B) The Western diet (WD) activated transcription of LXR in WT mice in association with increased Cyp7A1 gene expression. Lower p53 expression in p53^+/− mice is associated with lower gene expression of SHP. While no difference is seen in FXR and LXR, Cyp7A1 gene expression and BA levels are elevated.