Plays an important role in the regulation of embryonic development, cell proliferation, cell differentiation and cell migration. Required for normal brain, eye, ear and limb development during embryogenesis. Required for normal development of the gonadotropin-releasing hormone (GnRH) neuronal system. Plays a role in neurite outgrowth in hippocampal cells (By similarity). Cooperates with Wnt-1 in mouse mammary tumor virus-induced murine mammary tumorigenesis (PubMed:7884899). Monomer. Homodimer. Interacts with FGFR1, FGFR2, FGFR3 and FGFR4. Affinity between fibroblast growth factors (FGFs) and their receptors is increased by heparan sulfate glycosaminoglycans that function as coreceptors (By similarity). Additional isoforms seem to exist. Absent in normal mammary glands and detected only in adult testis and ovary and in midgestational embryos. By androgens. The N-terminus is blocked. Belongs to the heparin-binding growth factors family.