In this study, we further analyzed vascular endothelial function in the obesity mouse model and showed that the protein level of eNOS in the aortas of obese mice fed HFD was significantly higher than that of lean mice fed NC, while the activating eNOS-S1177 phosphorylation level was comparable between the two groups, which results in a decreased eNOS-S1177/total eNOS ratio (Figure 1A). Here, NOS3 is linked to obesity due to melanocortin 4 receptor deficiency.