Fig. 2. Effects of growth factors on glutamate uptake activity in astrocyte cultures. Astrocytes were treated with IGF-1, EGF, insulin, PDGF-AB or HGF for 24 hours, and the glutamate uptake activity was measured. The relative activity is expressed as a percentage of control levels. Of these growth factors, IGF-1 and EGF induced an increase in the uptake activity in a concentration-dependent manner. (*p<0.05; **p<0.01 vs control, Tukey’s test following ANOVA). Data are means±s.e.m. of 4-6 cultures.