neurotrophic factor and neuropeptide, primarily involved in the regulation of growth, maintenance, proliferation and survival of some target neurons. It may be a prototypical growth factor, as it was one of the first to be described. Since its isolation by Nobel Prize winners Rita Levi-Montalcini and Stanley Cohen in 1954, many biological processes involving NGFs have been identified, two of which are the survival of pancreatic beta cells and the regulation of the immune system.