ESR1 and cardiovascular disorder: In animal experiments, the basal release of endothelial-derived nitric oxide (EDNO) in aorta of wild-type male mice was significantly higher than that of wild-type female mice, while that of male estrogen receptor knockout (ERKO) mice was significantly lower than that of male wild-type mice, suggesting that the basal release of EDNO in aorta of mice was related to estrogen receptor, and it was speculated that the observed decrease of vascular estrogen receptor number might be a new risk factor for cardiovascular disease (21).