FGF 21 Rat

Fibroblast growth factors (FGFs) are a family of over 20 small (~17–26 kDa) secreted peptides. Initially characterized by their ability to stimulate fibroblast proliferation, these proteins exert their mitogenic activity through FGF receptors (FGFRs) 1, 2, or 3. A fourth closely related tyrosine kinase receptor (FGFR4) exhibits FGF binding but does not elicit a mitogenic response. FGFs regulate cellular activity through at least five distinct subfamilies of high-affinity FGFRs: FGFR-1, -2, -3, and -4, all possessing intrinsic tyrosine kinase activity and, with the exception of FGFR-4, multiple splice isoforms, and FGFR-5, which lacks an intracellular kinase domain. Increasing evidence suggests that FGFRs play a crucial role in regulating glucose and lipid homeostasis. Overexpression of a dominant negative form of FGFR-1 in cells induces diabetes in mice, implying that functional FGF signaling is essential for normal β-cell function and blood glucose control. FGFR-2 appears vital during pancreatic development, while FGFR-4 has been implicated in cholesterol metabolism and bile acid synthesis. FGF-19 has been shown to enhance resistance to diet-induced obesity and improve glucose and lipid profiles in diabetic rodents, potentially through desensitization mechanisms. These effects, partly mediated by observed changes in metabolic rates, suggest FGF-19 as a regulator of energy expenditure. FGF-21, primarily expressed in the liver, remains incompletely understood regarding its bioactivity and mechanism of action. However, it potently activates glucose uptake in adipocytes, protects against diet-induced obesity in transgenic mice overexpressing the protein, and lowers blood glucose and triglyceride levels in diabetic rodents upon therapeutic administration.

Recombinant Rat FGF 21, produced in E. coli, is a single, non-glycosylated polypeptide chain composed of 180 amino acids, with a molecular weight of 19.7 kDa. The purification process involves proprietary chromatographic techniques.

Sterile Filtered White lyophilized (freeze-dried) powder.

Lyophilized from a 0.2 µm filtered concentrated solution in 1xPBS, pH 7.4.

Reconstitute the lyophilized Rat FGF 21 in sterile 18 MΩ-cm H₂O at a concentration of at least 100 µg/ml. This solution can be further diluted in other aqueous solutions.

Lyophilized FGF 21, while stable at room temperature for 3 weeks, should be stored desiccated below -18°C. Upon reconstitution, store FGF 21 at 4°C for 2-7 days. For long-term storage, add a carrier protein (0.1% HSA or BSA) and store below -18°C. Avoid freeze-thaw cycles.

Purity exceeds 95.0% as determined by: (a) RP-HPLC analysis. (b) SDS-PAGE analysis.

The ED50, as determined by a cell proliferation assay using murine NIH/3T3 cells, is less than 700 ng/ml. This corresponds to a specific activity greater than 1.4 x 1000 IU/mg in the presence of 5 µg/ml of recombinant murine Klotho-beta.

Fibroblast growth factor 21, FGF-21.

Escherichia Coli.

AYPISDSSPL LQFGGQVRQR YLYTDDDQDT EAHLEIREDG TVVGTAHRSP ESLLELKALK PGVIQILGVK ASRFLCQQPD GTLYGSPHFD PEACSFRELL LKDGYNVYQS EAHGLPLRLP QKDSQDPATR GPVRFLPMPG LPHEPQEQPG VLPPEPPDVG SSDPLSMVEP LQGRSPSYAS