Fig. 3. Role of the NADPH oxidase in cardiomyogenesis of ES cells. (A) mRNA expression of Nox isoforms during ES-cell differentiation within embryoid bodies. Effects of H₂O₂ on protein expression of NADPH oxidase subunits in ES cell-derived cardiac cells (B) and neonatal cardiac cells isolated from mouse hearts (C). (D) Effects of H₂O₂ on Nox-1 and Nox-4 mRNA expression in embryoid bodies. (E) Inhibition of H₂O₂-induced cardiomyogenesis by the NADPH oxidase antagonists DPI (100 nM) and apocynin (10 µM). ^*P<0.05, significantly different to the untreated control.