PGE2 provokes the phosphorylation of CREB in orbital fibroblasts, an effect blocked with H89.

A: Confluent cultures were treated with PGE2 (1 µM) for different intervals. Cellular proteins were subjected to Western blot analysis of CREB and pCREB. Densitometric analysis of pCREB protein concentrations are expressed as the ratio to total CREB protein as a percent of the value at “0” min. Data are expressed as the mean ± SD of triplicate independent determinations. (* denotes statistical significance between treatment groups). B: H89 (10 µM) inhibits PGE2-provoked CREB phosphorylation in orbital fibroblasts. The inhibitor was added for 6 hrs, followed by addition of PGE2 (1 µM) for 15 min. Cellular proteins were subjected to Western blot analysis of pCREB protein using β-actin as a loading control.