Heparin-binding growth factor 1 is a protein that in humans is encoded by the FGF1 gene. FGF-1, unique among all 22 members of the FGF family, can bind to all seven FGF-receptor subtypes, making it the broadest-acting member of the FGF family, and a potent mitogen for the diverse cell types needed to mount an angiogenic response in damaged (hypoxic) tissues, where upregulation of FGF-receptors occurs. FGF-1 stimulates the proliferation and differentiation of all cell types necessary for building an arterial vessel, including endothelial cells and smooth muscle cells.
In mice with diet-induced diabetes, the equivalent of type 2 diabetes in humans, a single injection of the protein FGF1 is enough to restore blood sugar levels to a healthy range for > 2 days.