Evidence for FGF-like growth factor in adult bovine retina: analogies with EDGF I.

Eye Derived Growth Factor (EDGF) is the genus name for growth factor activities found in several ocular tissues. Purification from bovine retina by Cibacron blue affinity chromatography has previously given a fraction which can induce target cell proliferation at doses of 30 ng per ml of culture medium. Radioimmunoassay using a labelled synthetic decapeptide [Tyr 10]--FGF (1-10) including the 9 N terminal amino acids of brain Fibroblast Growth Factor (FGF) indicated that EDGF contained a FGF-like material. Further purification of Cibacron blue purified EDGF with heparin sepharose chromatography yielded two active fractions after elution with a sodium chloride gradient. One fraction named EDGF I eluted between 1.3 and 1.5 M NaCl and accounted for over 50% of the input biological activity and comigrated with purified FGF on SDS PAGE at a molecular weight of 16,000 d as a single band. FGF competed with EDGF I for binding to specific receptors on bovine epithelial lens cells. We conclude that retina contains a growth factor activity (EDGF I) similar if not identical to FGF.