Fig. 4.

Astrocyte production of tenascin in the presence of TGF-β1 is potentiated by bFGF. Astrocyte monolayers were grown in the presence of Sato’s N2 medium alone (N2) or in 50% activated macrophage-CM (M+), TGF-β1, bFGF, or a combination of TGF-β1 and bFGF for 48 hr. Western blot analysis of supernatants shows that TGF-β1 (A) and TGF-β1 and bFGF (B) cause a dose-dependent increase in tenascin production by astrocytes. C, Quantitation and comparison of the relative amounts of tenascin in the supernatants show that bFGF potentiates the effect of TGF-β1 by approximately twofold, increasing the ED₅₀ at lower concentrations of TGF-β1. Error bars represent the SD. The concentrations of TGF-β1 and bFGF combinations represent the amount of each factor.