FIGURE 5.

Induction of skeletal muscle Ucp3 gene expression is abolished by pharmacological removal of bile acids. A–C, male Wistar rats (n = 6) were fed high fat diets (45 kcal % fat) ad libitum for 46 days with either SPH or casein as the sole protein source. A, in skeletal muscle, SPH-fed rats exhibited reduced expression of Pparα and its target genes Acox1 and Mcad. B, muscle gene expression of Pparβ/δ and its target gene Adrp and Angptl4 was enhanced by SPH treatment. C, expression of genes related to fatty acid oxidation Cpt-1b and Ucp2 and -3 was enhanced in the SPH-treated rats. D, three groups of rats (n = 6) were pair-fed the same diets, plus the SPH diet with 0.5 weight % c'am for 46 days. Pharmacological removal of bile acids by 0.5 weight % cholestyramine completely abolished Ucp3 induction. mRNA levels are normalized to Gtf2b and relative to the expression in the casein-fed rats. Data are presented as mean ± S.E. Significant differences from casein-fed rats are denoted as follows: *, p < 0.05; **, p < 0.01.