Figure 3.

Effect of GF109203X on p38 MAP kinase activation in rat aortic SMC. After 72 h of exposure to several concentrations of glucose or mannitol, the cells were untreated, or treated with a PKC-specific inhibitor, GF109203X (GFX, 5 μM), for 30 min; then, the cells were lysed as described in Methods. (a) p38 MAP kinase activity measured by the phosphorylation of MBP using [γ-³²P]ATP. The results were derived from four separate experiments. **P < 0.01 vs. 5.5 mM glucose, ^#P < 0.05 vs. 16.5 mM glucose, ⁺P < 0.05 vs. 22 mM glucose. (b) Expression of p38 MAP kinase by immunoblot analysis. The samples were separated by 10% SDS-PAGE, transferred to PVDF membranes, and blocked overnight. The membranes were incubated with antiphosphospecific p38 MAP kinase and anti-p38 antibody. The arrowhead shows the phosphorylation of p38 MAP kinase. The results were derived from three separate experiments. (c) p38 MAP kinase activity by the phosphorylation of MBP using [γ-³²P]ATP. The results were derived from three separate experiments, with each experiment performed in duplicate. **P < 0.01 vs. 5.5 mM glucose. Each bar represents the mean ± SEM. PVDF, polyvinyldene difluoride.