1986 - Stanley Cohen, Rita Levi-Montalcini

Are there factors that influence nerve normal and abnormal development?

Levi-Montalcini showed that when tumors from mice were transplanted to chick embryos they induced potent growth of the chick embryo nervous system. Since the outgrowth didn't require direct contact, she concluded the tumor released a nerve growth-promoting factor. Cohen was the first to purify the NGF (nerve growth factor). It was found that during normal development nerve fibers grow towards the source of NGF, which is taken up in the fiber ends and transported back to the nerve cell body. Cohen also isolated, purified and characterized another growth factor, EGF (epidermal growth factor) which enhances a cascade of events including stimulation of glucose and amino acid transport, activation of protein synthesis and initiation of DNA synthesis and cell replication. These discoveries initiated a new era in the research area of neural development, and were followed by the identification of several other chemical growth factors.