Neurite outgrowth elicited by embryonic chick heart: partial purification of the active factor.

Chick heart explants stimulate a dense outgrowth of neurites in co-cultured spinal, sympathetic and ciliary ganglia. A factor sharing these properties was partially purified by gel filtration of extract prepared from lyophilized 18-day embryonic hearts. The active factor has an apparent molecular weight of roughly 40,000 and is evidently distinct from nerve growth factor (NGF) by stimulating the parasympathetic ciliary neurons and by lack of cross-reactivity with antibodies to NGF.