Fibroblast Growth Factors (FGFs) are a large family of proteins that regulate a range of physiological functions, such as embryonic development, metabolic regulation, angiogenesis, and tissue repair. FGF family activities are mediated by receptor tyrosine kinases and are facilitated by heparan sulfate. The FGF19 subfamily—composed of FGF19, FGF21, and FGF23—binds the alpha/beta-Klotho receptors. This novel regulatory system consists of vital homeostatic mechanisms, such as bile acid and cholesterol metabolism in the liver (FGF19), energy and glycolipids metabolism (FGF21), and phosphate, calcium and vitamin D metabolism in the kidneys (FGF23).
These kits are solid-phase sandwich ELISA kits using two kinds of highly specific antibodies to detect human FGF19 in EDTA plasma and cell culture supernatant (Cat. # 27996A) or human FGF21 in serum, EDTA plasma, and cell culture supernatant (Cat. # 27997A).
FGF19 is secreted in the intestine and transported to the liver through the bloodstream. It suppresses synthesis of bile in the liver and regulates liver functions to preserve sugar as a glycogen. FGF19 binds a receptor consisting of FGFR4 and beta-Klotho, and has been studied in relation to digestive and metabolic disorders.
FGF21 is secreted in the liver and has lipolytic action in fatty tissues. FGF21 binds a receptor consisting of FGFR and beta-Klotho. In response to fasting, lipid metabolism is increased, triacylglycerol is mobilized as fatty acids, and ketone bodies are produced, metabolized, and utilized as an energy source. It is believed that FGF21 is released during this process and possesses a hormone-like function.
The concentration of FGF19 is correlated with many disease such as polycystic ovary syndrome, coronary artery disease, impaired fasting glucose, quiescent Crohn's colitis, hepatocellular carcinoma, type 2 diabetes, and metabolic syndrome. The concentration of FGF21 is correlated with gestational diabetes mellitus, coronary artery disease, carotid atherosclerosis, non-alcoholic fatty liver disease, rheumatoid arthritis, diabetic nephropathy, type2 diabetes, and metabolic syndrome.