ABSTRACT
Nerve growth factor (NGF) is a neurotrophic protein which is involved in the terminal differentiation or functional maintenance of peripheral sympathetic and sensory neurons. In mammals, NGF is produced in exceptionally large amounts in a few exocrine glands which are subjected to sexual dimorphism. Serum levels of NGF were reported to be significantly higher in patients suffering from von Recklinghausen disease, but this observation was not confirmed in a further study. NGF-immunoreactive material was found by immunohistochemical procedures in cases of vasitis nodosa and prostatic adenocarcinoma. Several lines of evidence indicate that interleukin 1, a lymphokine released by activated macrophages, stimulates the production of NGF by primary Schwann cells or fibroblasts. In vivo, NGF promotes the survival, terminal differentiation, and the functional maintenance of postmitotic neurons, and in spite of its name, the factor has no obvious mitogenic activity on normal cells.
