FGF15

Fibroblast growth factor 15 is a is_associated_with::protein in mouse encoded by the Fgf15 is_associated_with::gene. It is a member of the is_associated_with::fibroblast growth factor (FGF) family but, like is_associated_with::FGF19, is_associated_with::FGF21 and is_associated_with::FGF23, has endocrine functions. is_associated_with::FGF19 is the orthologous protein in humans. They are often referred together as FGF15/19.

Identification
FGF15 was first described in developing mouse brain.

Fgf15 is syntenic with the human FGF19 gene. FGF15 and FGF19 proteins share about 50% amino acid identity, are found in the same tissues, and have similar functions in mouse and humans.

Functions
FGF15 is found in the absorptive cells of the mouse is_associated_with::ileum and play an important role in feedback inhibition of hepatic bile acid synthesis. FGF15 (and FGF19 in humans) function as hormones produced in response to is_associated_with::bile acid absorption acting on the farnesoid X receptor FXR, are secreted into the portal venous circulation and bind onto the liver membrane receptor is_associated_with::FGFR4/β-Klotho and repress bile acid synthesis by the Cyp7a1 gene.

In a mouse model of is_associated_with::chronic diarrhea due to is_associated_with::bile acid malabsorption, FGF15 administration, or stimulation of its production, reduced the bile acid loss by inhibiting new synthesis.

FGF15 also has effects on energy homeostasis. Fgf15-knock-out mice have reduced liver glycogen storage and are glucose-intolerant.