Figure 11.

Bile acids stimulate D2 expression in brown adipocytes. Schematic representation of the bile acid-TGR5–D2 pathway in brown adipocytes. Bile acids in the general circulation derived from the enterohepatic circulation potentially may stimulate TGR5 increasing cAMP, and thus leading to an increase in D2 expression in tissues where both proteins are coexpressed, e.g., BAT and skeletal muscle. This pathway has been shown to increase energy expenditure and protect against diet-induced obesity in mice (171). [Reproduced in part with permission from Baxter and Webb: Nature 439:402–403, 2006 (446).]