Gene expression in wild-type and Cyp8b1–/– mice. (a) mRNA levels for the indicated genes were determined by blotting in male mice (n = 6 per group) of the indicated genotypes. Autoradiographic exposure times varied from 7 to 18 hours. (b and c) SHP and IBABP mRNA levels were quantitated in the livers and/or five intestinal segments (proximal to distal, S1-1 to S1-5) of male mice of the indicated genotype by real-time PCR in the presence of the intercalating dye SYBR Green. Levels of cyclophilin mRNA in each sample were used to normalize the results. The numbers shown are the averages of triplicate determinations for each mRNA and tissue. Oatp2, organic anion transporter 2 (also known as SLC21A3); SR-BI, scavenger receptor BI.