Effect of the absence of CAR on mRNA of BA synthesis and regulation in livers of male and female mice. Livers were collected from male and female, wild-type (WT), and CAR-null mice (n ≥ 5 mice per group). Total RNA was analyzed by QuantiGene Plex 2.0 Assay, as well as by RT-qPCR. Relative mRNA levels were calculated with vehicle controls set as 100%. Data represent means ± SEM. Asterisks (*) denote statistical differences from respective male or female WT mice (p < .05). Abbreviations: Baat, Bile acid CoA:amino acid N-acyltransferase; Bal, bile acid CoA ligase; Cyp, cytochrome p450; FXR, farnesoid x receptor; F, females; Fgfr4, fibroblast growth factor receptor; Hnf4α, hepatocyte nuclear factor 4α; Lrh-1, liver receptor homolog-1; M, males; Shp, small heterodimer partner; WT, wild-type. Color image is available in the online version of the article.