Figure 5.

Effect of MEK inhibitor PD98059 on insulin secretion and ERK1/2 activation in INS-1 cells. Cells were preincubated in 0 mM glucose for 1 h and then treated with agents as indicated for 2 h. PD98059 (100 μM) was included in all stages of the experiment from the 1 h preincubation to the 2 h treatment for the relevant samples. Immunoblots using active ERK antibody (A) and Y691 (B) and a corresponding immune complex kinase assay with X837 antibody using myelin basic protein as substrate (C) are shown. Matching insulin secretion profiles are also shown (D). One of three experiments is shown.