A) Pooled data from sarcomere shortening transients in cardiac myocytes isolated from NOX2 KO (n=4) mice, NOX4 KO (n=5) mice, or wild-type controls (n=7 mice). Cardiac myocytes were stimulated with isoproterenol (10 nM, 5 min) with or without insulin pretreatment (10 nM, 30 min). (B) Representative immunoblots of NOX2 or NOX4 KO cardiac myocytes treated with isoproterenol with or without insulin pretreatment (right side of the blots). wild-type cardiac myocyte lysates were loaded on the left side of the gel. Below the representative blots are the densitometric analyses of pooled data from at least three independent experiments. * indicates p<0.05, **p<0.01, and ***p<0.001.