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. Acts both upstream of kdr and tie1 to stimulate endothelial cell differentiation, and upstream of gata1 to stimulate hematopoietic cell differentiation. Homodimer; disulfide-linked (By similarity). Isoform VEGF165 binds kdr and kdrl. Predominantly expressed in regions associated with active vascularization. From 15-16 hours post-fertilization (hpf), expressed in the anterior forebrain, the mesoderm underlying and lateral to the anterior hindbrain, the mesoderm underlying and lateral to the posterior hindbrain, and in the ventral medial portions of the somites. By 30-36 hpf, expression in the somites is decreased, while strong expression is observed in the region of the developing glomeruli and in the anterior portion of the pronephric ducts, the pharyngeal arches, and the brain. By 72 hpf, expression remains only in the pronephros region. Expressed both maternally and zygotically. Present throughout embryonic development, and in adults. Belongs to the PDGF/VEGF growth factor family.