Albumin-induced increase in p38 mitogen-activated protein kinase (MAPK) and Jun kinase (JNK) is mediated by reactive oxygen species. Representative pictures and corresponding quantification of western blot of the level of phosphorylated (a) p38 MAPK, (b) extracellular signal regulated protein kinase (ERK), and (c) JNK in cells treated with vehicle or BSA in the presence (+) or absence (−) of the NADPH oxidase inhibitor, diphenyleneiodonium chloride (DPI). Treatment with DPI suppresses the increase in phospho-p38 MAPK and JNK but induces a further increase in the level of phospho-ERK induced by albumin treatment. The data are representative of mean ± SEM of two independent experiments. * P < 0.05, ***P < 0.001 compared with the BSA-treated group.