Tauro-β-muricholate (TBMC) enrichment of the bile acid pool after intestinal Gata4 deletion is due to an increase in TBMC uptake. (a) Real-time reverse transcriptase–PCR shows that the mRNAs for hepatic bile acid biosynthetic enzymes, Cyp7a1, Cyp8b1, Cyp27 and Cyp7b1, are similar between Wt-control and G4ap mice (n=5 in each group). Values are presented relative to the mean value of Wt-control liver samples. (b) Segmental analysis of the bile acid composition of luminal contents reveals that the TMBC/taurocholate (TC) ratio as a percentage of segment I increases distally in Wt-controls, but decreases distally in the G4ap mice. *p<0.05 as compared with Wt-controls, n=3–6 in each group.