Fibroblast growth factor 21 is a protein that in humans is encoded by the FGF21 gene, which is also a member of the fibroblast growth factor (FGF) family. The gene is mapped on 19q13.33. Using RT-PCR, Fgf21 was expressed in several types of adipose tissue in mice, including subcutaneous and epididymal fat pads and brown adipose tissue. The level of expression in adipose tissue was comparable to that in liver. 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 also protects animals from diet-induced obesity when overexpressed in transgenic mice and lowers blood glucose and triglyceride levels when administered to diabetic rodents. Changes in Fgf21 expression due to suckling or nutritional manipulations were associated with changes in circulating free fatty acid and ketone body levels. In differentiated mouse brown adipocytes in culture, Fgf21 treatment increased the expression of thermogenic genes, caused higher total and uncoupled respiration, and enhanced glucose oxidation.

Differences in protocols and secondary/substrate sensitivity may require the FGF21 antibody to be titrated for optimal performance.

Amino acids H29-S209 from the human protein were used as the immunogen for the FGF21 antibody.

After reconstitution, the FGF21 antibody can be stored for up to one month at 4oC. For long-term, aliquot and store at -20oC. Avoid repeated freezing and thawing.