Fig. 5.

Inhibitors of ERK1/2 attenuate H₂O₂-induced ERK2 and S6K1 phosphorylation in H4IIE cells. Cells were pre-treated with 10 μM PD98059 or 10 μM UO126 for 15 min before addition of H₂O₂. Sixty min later, the cells were lysed and phosphorylation of (A) ERK2 and (B) S6K1 was assessed by Western blot analysis as described under “Materials and Methods”. Representative blots are shown as insets to each panel. Lane 1, control cells; lane 2, cells incubated for 60 min with 0.5 mM H₂O₂; lane 3, cells incubated for 60 min with 3 mM melatonin followed by a 60 min incubation with both melatonin and H₂O₂; lane 4, cells incubated for 2 h with 3 mM melatonin. Bars not sharing the same letter are significantly different, p<0.05.