Vascular endothelial cell effectors in fetal calf retina, vitreous, and serum

The vascular endothelial growth factor or factors (VGF) and the cytotoxic component(s) in fetal calf retinal extract, vitreous, and serum were investigated. A new quantitative method of measuring the cell growth stimulatory activity and cytotoxicity was used. Results obtained in this study suggest that the VGF may be present in retina, vitreous, and serum in situ. The VGF was found to be specific for fetal aortic endothelial cells. The VGF was diffusible and could be readily separated by dialysis from the nonspecific cell growth stimulatory factor(s) also present in retinal extract, vitreous, and serum. The VGF activity in the dialyzable fraction was stable at pH 3 and with heat treatment. The VGF appeared to consist of up to three components: VGFI, VGFII, and VGFIII. These components could be separated by cation-exchange chromatography, with an identical elution pattern for each component regardless of tissue origin. Serum and retinal extract contained all three components, whereas in vitreous, VGFIII was either negligible or totally lacking. The cytotoxic component(s) was found only in vitreous and serum, and its cytotoxicity appeared to be nonspecific.