A 50-base synthetic oligodeoxynucleotide complementary to a portion of mouse nerve growth factor (NGF) mRNA was used as a probe for analysis of the expression of NGF gene. Northern blot analysis showed the presence of a major 1.3 kb transcript, which was identical in size to mouse NGF mRNA, in both C6Bu1 cells and rat astrocytes cultured from newborn rat brain. Further, the rearrangement of DNA sequence in and around the NGF gene locus of C6Bu1 cells was not detected by Southern blot analysis. These results indicate the expression of NGF mRNA in both C6Bu1 cells and astrocytes from rat brain, suggesting that astrocytes may produce NGF protein in the rat brain, especially in developing rat brain. © 1987.