NOS3 and endothelial dysfunction: 2013). We found that HFD reduced nitrate/nitrite concentration, which is rapidly oxidized from NO, (Fig. 4A) and eNOS expression (Fig. 4B, 32% lower vs. LF‐SED, P = 0.051) in mouse cardiac tissues. Gamez‐Mendez et al. (2015) have reported that HFD treatment reduced coronary NO production and endothelial dysfunction in obese mice, and Yang et al. (2007) have shown a down‐regulation of aortic eNOS expression in HFD‐induced obese rats. Previously, we have demonstrated that HFD impaired NO‐mediated coronary arteriolar vasodilatation in obese mice (Park et al. 2012).