Figure 6. Influence of VEGFR-2 on apical and basal VEGF-A secretion. In the RPE/choroid, the inhibition of vascular endothelial growth factor (VEGF)-2 reduces VEGF-A secretion on the apical side (A) but not on the basal side (B). In contrast, in primary RPE cell culture, the inhibition of VEGFR-2 did not influence the secretion of VEGFR-2, at the apical side (C) or at the basal side (D). Supernatants were collected for 24 h and were analyzed in enzyme-linked immunosorbent assay (ELISA). In the whole cell lysis of the primary RPE cells, analyzed with western blot, a significant reduction was found in VEGF-A expression after 48 h of VEGFR-2 inhibition. Representative blots of VEGF-A and β-actin control are shown, as well as a densitometric evaluation of VEGF-A normalized for β-actin (E). Significance was determined with the Student t test; + p<0.01, ++ p<0.01. n=4 (A), n=3 (B), n=6 (C–E). Bars depict the mean and the standard deviation.