Fibroblast growth factor 19 (FGF19) is a secreted protein which belongs to the FGFs family. FGF19 is expressed in fetal brain, cartilage, retina, and adult gall bladder. FGFs modulate cellular activity via at least 5 distinct subfamilies of high-affinity FGF receptors (FGFRs): FGFR-1, -2, -3, and -4, all with intrinsic tyrosine kinase activity. FGFRs can be important for regulation of glucose and lipid homeostasis. FGF19 has important roles as a hormone produced in the ileum in response to bile acid absorption. It has been shown to cause resistance to diet-induced obesity and insulin desensitization and to improve insulin, glucose, and lipid profiles in diabetic rodents. FGF19 can be considered as a regulator of energy expenditure.
FGF19, also known as FGF-19, 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. FGF19 interacts with FGFR1, FGFR2, FGFR3 and FGFR4. Affinity between fibroblast growth factors (FGFs) and their receptors is increased by KL, KLB and heparan sulfate glycosaminoglycans that function as coreceptors. It interacts with KL and KLB directly. However, it interacts with FGFR4 in the presence of heparin, KL or KLB. FGF19 is involved in the suppression of bile acid biosynthesis through down-regulation of CYP7A1 expression, following positive regulation of the JNK and ERK1 2 cascades. It also stimulates glucose uptake in adipocytes.