Abstract: Objective To explore the relation between the MEK1 signal transduction pathway and the synthesis of γ-glutamylcysteine synthetase(γ-GCS)in the bronchial epithelial cell(16-HBE). Methods 16-HBE cells were incubated with the PD98059(50 μmol/L)for 2, 8, 16 and 24 hours. The expression of γ-GCS mRNA and protein was measured by Western blotting and real-time PCR. Cellular GSH level was detected by staining method. C-jun was examined by Western blotting. Results After the incubation with the PD98059 for 4、8、16 and 24 hours, the expression ofγ-GCS, γ-GCS mRNA and GSH increased, but the expression of c-jun decreased as compared to the control group. Conclusions PD98059, inhibitor of MEK1, can increase the synthesis of γ-GCS and GSH in the 16-HBE. Blocking AP-1 could not decrease the synthesis of γ-GCS and GSH.