Expression of nerve growth factor family neurotrophins in a mouse osteoblastic cell line.

With cultured osteoblastic cells, clone MC3T3-E1 derived from newborn mouse calvaria, the mRNAs encoding three representative neurotrophins, namely, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), were proved in estimation by the polymerase chain reaction (PCR) method. The increase and then subsequent decrease of all three mRNAs within the proliferation phase were followed by their gradual increase in the differentiation phase, with a tendency of enhancement by exogenous TGF-beta as was particularly evident in the case of NGF. These findings were further substantiated by identification of NGF-like neutrophils in the conditioned medium of the osteoblastic cells by an immunoblotting and neurite extension assay.