Brain extracts that promote the proliferation of neuroblasts from chick embryo in culture.

The effects of brain and meningeal extracts from chick embryos on the proliferation of cultured neuroblasts from chick embryo cerebral hemispheres were studied. Morphological observations, counts of the cultured neurons, determination of DNA and protein contents as well as [3H]thymidine incorporation measurements were made to evaluate the proliferative activity of the neuroblasts. We demonstrated a stimulatory effect of brain extract from 8-day-old embryos on the proliferative activity of neuroblasts from chick embryos younger than 7 days. Brain extracts from older chick embryos and meningeal extract possess less stimulatory effect.