A TERATOCARCINOMA-DERIVED NEUROTROPHIC ACTIVITY

IN a search for nerve growth factor (NGF) in tissue extracts of a muri ne transplantable teratocarcinoma that harbours immature neural tissue in abundance, a trypsin-sensitive and heat labile neurotrophic activi ty was identified. The final protein fraction obtained by cation excha nge chromatography contained five proteins with mel. wts ranging from 52 to 72 kD. It supported the growth and differentiation of immature n eurones in neonatal rat cerebellar cultures but had no effect on embry onic chick dorsal root ganglia which are the classical targets for NGF .