Growth factor active in angiogenesis, vasculogenesis and endothelial cell growth. Induces endothelial cell proliferation, promotes cell migration, inhibits apoptosis and induces permeabilization of blood vessels. Binds to the FLT1/VEGFR1 and KDR/VEGFR2 receptors, heparan sulfate and heparin (By similarity). Homodimer; disulfide-linked. Also found as heterodimer with PGF (By similarity). Additional isoforms seem to exist. Widely expressed. Abundantly and equally expressed in heart and liver. In kidney glomeruli, brain and yolk sac, isoform VEGF-166 is 5- to 10-times more abundant than isoform VEGF-190. Isoform VEGF-166 is expressed early at day 1 and increases during gastrulation. Expression of isoform VEGF-190 is detectable only from day 2. Isoform VEGF-190 contains a basic insert which acts as a cell retention signal. Belongs to the PDGF/VEGF growth factor family.