The aim of the current study was to determine whether basic fibroblast growth factor (bFGF), regulates the release of transforming growth factor-beta1 (TGF-beta1) from C6 glioma cells. The results of the study show that bFGF (2, 5 and 10 ng/ml) dose dependently induced the release of TGF-beta1 from C6 glioma cells, with the 10 ng/ml dose inducing a 2- to 3-fold increase of TGF-beta1 levels. This effect was evident as early as 6 h following treatment, with maximal levels observed at 18 h. The effect of bFGF was largely on latent TGF-beta1, and was isoform specific, as bFGF had no effect on TGF-beta2 release. The bFGF effect on TGF-beta1 was also glioma specific, as no such stimulatory effect was observed in rat cortical astrocytes.