a protein (MW about 27,000) that controls the development of sympathetic postganglionic neurons and possibly also sensory (dorsal root) ganglion cells in mammals; similar factors have been isolated from the venom of several species of snakes; it has been isolated from the submaxillary glands of male mice, and when it is injected into newborn animals, sympathetic ganglia become hyperplastic and hypertrophic; stimulates synthesis of nucleic acids and protein.
