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. May play a role in increasing vascular permeability during lactation, when increased transport of molecules from the blood is required for efficient milk protein synthesis. Binding to NRP1 receptor initiates a signaling pathway needed for motor neuron axon guidance and cell body migration, including for the caudal migration of facial motor neurons from rhombomere 4 to rhombomere 6 during embryonic development (By similarity). Also binds the DEAR/FBXW7-AS1 receptor (By similarity). Homodimer; disulfide-linked (PubMed:7706320). Also found as heterodimer with PGF (PubMed:7706320). Interacts with NRP1 (By similarity). Interacts with isoform 2 of BSG (By similarity). VEGF-A120 is acidic and freely secreted. VEGF-A164 is more basic, has heparin-binding properties and, although a significant proportion remains cell-associated, most is freely secreted. VEGF-A188 is very basic, it is cell-associated after secretion and is bound avidly by heparin and the extracellular matrix, although it may be released as a soluble form by heparin, heparinase or plasmin (By similarity). Additional isoforms seem to exist. Expressed in the pituitary, in brain, in particularly in supraoptic and paraventricular nuclei and the choroid plexus. Also found abundantly in the corpus luteum of the ovary and in kidney glomeruli. Expressed in the ductal epithelial cells of post-pubertal mammary glands. Expressed in the ductal and alveolar epithelial cells throughout the whole period of gestational evolution, lactation and involution. Increases during pregnancy (5.0-fold increase on day 12 with a subsequent decrease on day 18) and during lactation (18.5-fold increase on day 7). Levels appear to be minimally altered during involution. Belongs to the PDGF/VEGF growth factor family.