Fig. 5

Administration of high glucose for 24 h attenuated IRβ total expression and its phosphorylated form in HUVECs. Physiological insulin increased IRβ tyrosine phosphorylation only for the condition of NG. Previously exposed to 24 h of 5 mmol/L (NG) or 25 mmol/L (HG) of glucose, cells were stimulated with different insulin concentrations for 30 min. Whole cell lysates were prepared for immunoblot analysis of the phosphorylated form of IRβ and the total amount of IRβ protein. The panels show representative images of different independent experiments. Densitometric values were normalized to total amounts of IRβ and actin, as indicated. Bars represent mean ± SEM for five independent experiments. *P < 0.05, **P < 0.01 HG vs. NG