FIGURE 4.

eNOS signaling participates in endothelial cell responses to vildagliptin. A and B, time-dependent changes in the phosphorylation of Akt and eNOS signaling in HUVECs treated with 5 nm vildagliptin and/or 5 nm GLP-1. Shown are quantitative analysis of relative changes in phosphorylated Akt and eNOS. Relative phosphorylation levels were normalized to each total protein signal (n = 3). *, p < 0.05 versus control (0 min). C, contribution of PI3K and eNOS to vildagliptin-mediated endothelial cell differentiation. HUVECs were pretreated with LY294002 (50 μmol/liter), l-NAME (1 mmol/liter), or vehicle (dimethyl sulfoxide), and treated with 5 nm vildagliptin and/or 5 nm GLP-1 at 37 °C for 6 h (n = 3). The Matrigel assay was performed. Quantitative analyses of the network tube length are shown. Results are shown as the mean ± S.D. (n = 5). *, p < 0.05; **, p < 0.01.