Measured by its ability to neutralize FGF‑23-induced proliferation in the NIH‑3T3 mouse embryonic fibroblast cell line. The Neutralization Dose (ND50) is typically 5-15 µg/mL in the presence of 1 µg/mL Recombinant Human FGF‑23, 5 µg/mL Recombinant Mouse Klotho, and 10 µg/mL heparin.
Please Note: Optimal dilutions should be determined by each laboratory for each application. General Protocols are available in the Technical Information section on our website.
Cell Proliferation Induced by FGF‑23 and Neutralization by Human FGF‑23 Antibody. In the presence of Recombinant Mouse Klotho (5 µg/mL, Catalog # 1819-KL) and heparin (10 µg/mL), Recombinant Human FGF‑23 (Catalog # 2604-FG) stimulates proliferation in the NIH‑3T3 mouse embryonic fibroblast cell line in a dose-dependent manner (orange line). Under these conditions, proliferation elicited by Recombinant Human FGF‑23 (1 µg/mL) is neutralized (green line) by increasing concentrations of Goat Anti-Human FGF‑23 Antigen Affinity-purified Polyclonal Antibody (Catalog # AF2604). The ND50 is typically 5‑15 µg/mL.
Preparation and Storage
Reconstitute at 0.2 mg/mL in sterile PBS.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. *Small pack size (SP) is shipped with polar packs. Upon receipt, store it immediately at -20 to -70 °C
Stability & Storage
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.
Fibroblast growth factor 23 (FGF-23) is a 30-32 kDa member of the FGF family, within a subfamily that also includes FGF-19 and FGF-21. FGF proteins contain a 120 amino acid (aa) core FGF domain that exhibits a beta -trefoil structure (1, 2). FGF-19 subfamily members are highly diffusible molecules owing to their poor ECM/heparin sulfate binding and plasma-stabilizing intramolecular folds (2-4). Mature human FGF-23 contains an atypical (very low affinity) heparin binding site (aa 134‑162), a proteolytic cleavage site (Arg179-Ser180), and multiple O-linked glycosylation sites with Thr178 being of particular importance (4-7). O-linked glycosylation at Thr178 blocks the cleavage of FGF-23, thereby preventing loss of FGF-23 activity (7, 8). Mature human FGF-23 shows 72% aa identity to mouse FGF-23 and is active on mouse cells (6). FGF-23 exerts its effects through a ternary complex that includes Klotho and an FGF receptor (FGF R4 or the "c" isoforms of FGF R1 or FGF R3). Klotho has a restricted distribution that limits FGF-23 activity (9-11). FGF-23 is produced by osteocytes and osteoblasts in response to high circulating phosphate levels, elevated parathyroid hormone, and circulatory volume loading. It functions as an endocrine phosphatonin by suppressing circulating phosphate levels (12). FGF-23 interaction with renal proximal tubular epithelium decreases the renal resorption of phosphate by downregulating phosphate transporters and by suppressing vitamin D production. It also decreases the intestinal absorption of phosphate (13).
Mohammadi, M. et al. (2005) Cytokine Growth Factor Rev. 16:107.
Fukumoto, S. (2007) Endocr. J. Sep 14; [Epub ahead of print].
Goetz, R. et al. (2007) Mol. Cell. Biol. 27:3417.
Harmer, N.J. et al. (2004) Biochemistry 43:629.
Yamashita, T. et al. (2000) Biochem. Biophys. Res. Commun. 277:494.
Shimada, T. et al. (2001) Proc. Natl. Acad. Sci. USA 98:6500.
Frishberg, Y. et al. (2007) J. Bone Miner. Res. 22:235.
Kato, K. et al. (2006) J. Biol. Chem. 281:18370.
Zhang, X. et al. (2006) J. Biol. Chem. 281:15694.
Urakawa, I. et al. (2006) Nature 444:770.
Kurosu, H. et al. (2006) J. Biol. Chem. 281:6120.
Razzaque, M.S. and B. Lanske (2007) J. Endocrinol. 194:1.
Kurosu, H. et. al. (2007) J. Biol. Chem. 282:26687.
R&D Systems personnel manually curate a database that contains references using R&D Systems products.
The data collected includes not only links to publications in PubMed,
but also provides information about sample types, species, and experimental conditions.
The reconstitution calculator allows you to quickly calculate the volume of a reagent to reconstitute your vial. Simply enter the mass of reagent and the target concentration and the calculator will determine the rest.