Fibroblast growth factor 21 is a protein that in humans is encoded by the FGF21 gene. By genomic sequence analysis, Nishimura et al.(2000) identified the FGF21 gene within the 5-prime flanking region of the FUT1 gene on chromosome 19. The protein encoded by this gene is a member of the fibroblast growth factor(FGF) family. FGF family members possess broad mitogenic and cell survival activities and are involved in a variety of biological processes including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. FGF21 stimulates glucose uptake in adipocytes but not in other cell types. This effect is additive to the activity of insulin. FGF21 treatment of adipocytes is associated with phosphorylation of FRS2, a protein linking FGF receptors to the Ras/MAP kinase pathway. FGF21 injection in ob/ob mice results in an increase in Glut1 in adipose tissue. FGF21 also protects animals from diet-induced obesity when overexpressed in transgenic mice and lowers blood glucose and triglyceride levels when administered to diabetic rodents.
