Proliferative effect of G-CSF, SCF, and its combination on murine cerebral endothelial cells in vitro. A mouse brain endothelial cell line (b.end3) was used in the experiment. Following a 24-hour incubation of the cells with the factors at different concentrations (values are mean nanograms per milliliter media) and BRDU, the proliferation rate was calculated based on optical density (OD) measurements. represents proliferation at normoxic conditions; ■ shows proliferation rate in hypoxic conditions. Controls received no factors but BRDU. G-CSF seems to be ineffective in the concentrations used, while SCF has a dose-dependent, significant proliferative effect, starting at 5 ng/mL. Combining the 2 factors results in proliferation rates similar to that of SCF alone. Hypoxic conditions seem to further increase the effectiveness of SCF. Values are means plus SD.