NOX4 and diabetes mellitus: Summer and diabetes resulted in myocardial NF‐κB activation and Nrf2 inactivation (as assessed by the nuclear accumulation of p65 and Nrf2, respectively), and these changes appeared to correlate with the increased expression of the O2− ‐forming Noxs and the decreased expression of Nox4, respectively (Fig. 3, Table 2).