Figure 3.

Effects of Syk and Wortmannin on H₂O₂-induced IP₃ production. (A) Complete abolishment of H₂O₂-induced IP₃ production in Syk-negative cells. DT40 cells were stimulated with 5 mM H₂O₂ for the times indicated, and IP₃ concentrations in the extracts were assayed as described in Materials and Methods. Shown are the mean values of three independent measurements. (B) Partial inhibition of H₂O₂-induced IP₃ production by Wortmannin. DT40 cells were pretreated with 100 nM Wortmannin for 10 min and then stimulated with 5 mM H₂O₂. The data presented are the mean values of three independent measurements.