Recombinant human basic fibroblast growth factor (rhbFGF) was found to induce secretion of nerve growth factor (NGF) in cultured astrocytes from rat brain. The induction was concentration dependent; a maximum increase of 2-fold was observed at concentrations of 3-10 ng/ml or rhbFGF. When rhbFGF was added to the astrocytes, the induction occurred within 8 h and leveled off after 12 h. Antiserum against rhbFGF completely blocked the induction. Maximum induction occurred under serum-free culture conditions and in cultures with a high cell density. These results suggest that rhbFGF may exert a neurotrophic effect on the central nervous system through the induction of NGF secretion by astrocytes.