Nerve growth factor secreted by mouse heart cells in culture

Mouse heart cells in culture synthesized and secreted a nerve growth factor (NGF) which cross-reacted with mouse submaxillary gland beta NGF. The synthesis of NGF by heart cells was greatly reduced by addition of actinomycin D or cycloheximide but not by cytosine arabinoside, suggesting that the synthesis of NGF by heart cells required DNA transcription but not DNA replication. Heart NGF and beta NGF were virtually equivalent with respect to the neurite outgrowth stimulating activity and immunologically indistinguishable. The molecular weight of heart NGF estimated by the gel filtration method was identical with that of beta NGF. Isoelectric point of heart NGF was about 9.5, like beta NGF. These results suggest that NGF synthesized and secreted by mouse heart cells is an identical molecule to beta NGF of the mouse submaxillary gland.