Bile acids are taken up by enterocytes, epithelial cells of the small intestine, where they can activate the nuclear receptor farnesoid X receptor (FXR). This causes the production of fibroblast growth factor 19 (FGF19) which is then transported out of the enterocyte to the portal vein. While most FGF19 goes to the liver, some FGF19 instead enters systemic circulation where it can cross the blood brain barrier and interact with its receptors in the brain. Beta-klotho is a transmembrane protein that promotes the interaction of FGF19 and the receptor to form a stable complex. FGF receptor signaling likely plays a role in energy and glucose metabolism.

Bile Acid Indirect Signalling Pathway References