7S nerve growth factor has different biological activity from 2.5S nerve growth factor in vitro.

It is considered that two molecular forms of nerve growth factor (NGF), that is 7S NGF and 2.5S NGF have the identical neurotrophic effect on neurons. We now report that 7S NGF has different biological activities from 2.5S NGF in vitro. 7S NGF could promote the survival and neurite outgrowth of neurons from newborn rat hippocampus, cortex and cerebellum and stimulate the proliferation of astrocytes in vitro, but 2.5S NGF had no such effect.