['Culture of retinal pigment epithelium (RPE) cells might be a future option in the therapy of various degenerative retinal diseases. However, the molecular changes which occur during in vitro expansion of RPE cells during culture are not fully elucidated. The aim of this study was to evaluate molecular changes in the RPE cell line ARPE-19 after stimulation with different growth factors.', 'Cultured ARPE-19 cells were stimulated for 72 hours with rh-EGF, rh-IGF-1, rh-VEGF or rh-bFGF, and transcriptional changes of the differentiation markers cytokeratin 18 and RPE65 and of the key molecules of the wnt pathway, beta-catenin, and glycogen synthase kinase-3 (GSK-3) were evaluated by real time RT-PCR.', 'We found a significant decrease of cytokeratin 18 and RPE65 transcription after stimulation with rh-EGF (0.47 +/- 0.42 and 0.32 +/- 0.57-fold, respectively; p < 0.05). A significant reduction of beta-catenin and GSK-3 mRNA was found in ARPE-19 cells stimulated with rh-IGF-1 (0.61 +/- 0.25 and 0.52 +/- 0.02-fold, respectively) or rh-EGF (0.55 +/- 0.19 and 0.76 +/- 0.26-fold, respectively). No changes of beta-catenin mRNA were observed after stimulation with rh-VEGF or bFGF.'] Does epidermal growth factor inhibit glycogen synthase kinase-3 ( GSK-3 ) and beta-catenin transcription in cultured ARPE-19 cells?