Fibroblast Growth Factor Immunoreactivity Research Articles

Immunoreactive fibroblast growth factor (FGF) in rat tissues: Molecular weight forms and the effects of hypophysectomy

Rat tissues were extracted at neutral pH with dilute (0.15 M) ammonium sulfate and examined for presence of fibroblast growth factor immunoreactivity (ir-FGF). Ir-FGF was found in substantial amounts in all the tissues but higher amounts were found in liver and kidney. Gel filtration column chromatography showed the presence of three molecular weight peaks of ir-FGF, one associated with the void volume (the major form in kidney extract), another with an apparent molecular weight of 150–180,000 Da (the major form in serum) and a third one of 70,000 Da (the major form in the other tissues examined: pituitary, brain, liver, spleen and thymus). No immunoreactivity coeluted with authentic FGF purified from bovine pituitary glands, suggesting that FGF is present in neutral extracts in association with binding molecules and/or precursors. Hypophysectomy had no major effect on ir-FGF in the tissues, but increased its amount in serum. The results establish a wide distribution of FGF in several embryologically, morphologically and developmentally distinct tissues and indicate that the pituitary is not the major source of FGF immunoreactivity, although it can be involved in the regulation of plasma levels.

Immunoreactive fibroblast growth factor in cells of peritoneal exudate suggests its identity with macrophage-derived growth factor

Peritoneal exudate cells were collected from thioglycollate stimulated mice, extracted an examined for the presence of immunoreactive and bioactive fibroblast growth factor (FGF). The crude extract stimulated in a dose dependent fashion the proliferation of vascular endothelial cells derived from the bovine aortic arch. The extract also showed a parallel and dose-dependent inhibition of binding in a highly specific radioimmunoassay for FGF. The immunoreactive FGF (ir-FGF) contained in the extract was retained on a heparin-sepharose affinity column as is characteristic of pituitary FGF. Reversephase HPLC of the macrophage-derived material reveals one biologically active form of FGF which coelutes with the major form of immunoreactivity. The results demonstrate the presence of FGF in these cells and suggest that at least one of the hitherto unidentified mitotic activities in these extracts is due to a mitogen indistinguishable from FGF.