Dose-dependent effect on aortas without endothelial cells after 17β-estradiol (E2) or 4,4′,4″-(4-propyl-[1H]pyrazole-1,3,5-triyl)tris-phenol (PPT) treatment in male and female mice. A: increased vessel relaxation at 10−5 M E2 compared with vehicle controls in both male and female mice was found (n = 3 per sex in each treatment group, ##P < 0.01, E2 treatment vs. vehicle controls in female mice; ###P < 0.001, E2 treatment vs. vehicle controls in male mice). However, there was no sex difference in E2-induced vessel relaxation in endothelium-denuded aortas (n = 3 per sex). B: bar graph of A at 10−5 M E2. C: the estrogen receptor-α agonist PPT induced vessel relaxation in aortas without endothelial cells from both wild-type male and female mice. However, no significant differences were found between male and female mice in PPT-induced vessel relaxation (n = 3 per sex). D: bar graph of C at 10−5 M PPT.