Purification and metabolic effects of a nerve growth-promoting protein from snake venom.

A factor which specifically stimulates the growth of sensory and sympathetic nerve cells has been under investigation in this laboratory for a number of years. The growth stimulation is demonstrable both in tissue culture, on isolated nerve ganglia, and in the living chick embryo. The factor was originally discovered in certain mouse sarcomas (2-5) and the biological activity was found to reside in a protein fraction obtained from these tumors (6). A much more potent source of the nerve growth factor has recently been found in the sa.livary glands and salivary secretions of a variety of species. These include snake venom (7), the venom of the Gila monster, the saliva and salivary glands of the mouse, and the salivary glands of the rat and hamster (1). The venom and mouse salivary gland factors duplicated the growth promoting effects of the tumor both in tissue culture and in viva, when they were injected into the chick embryo (8,9). This paper is concerned with two main problems: (a) the chemical nature of the venom growth factor and (b) its mode of action and metabolic effect on the nerve cell.