ARPE-19 cells were incubated for 12 h with iso-osmolar or hyperosmolar (Na25, Na50, Na100, Su50, Su100 and Su200) medium. TonEBP protein levels were determined by semiquantitative western blot analysis. β-actin was used as an internal control of protein expression. Band densities were estimated using an imaging system as described under Material and Methods. TonEBP protein level (ratio of TonEBP band density over β-actin band density) was expressed as percent of the control value (iso-osmolar condition, set to 100%) and are the mean ± SEM (n=3). For both NaCl and sucrose stimulation, statistical analyses were performed using repeated measures ANOVA and Dunnett’s post-hoc tests.* indicates p<0.05 compared to Iso-osmolar condition.