Figure 2

Effect induced by 17α- and 17β-E2 on uterine contraction achieved by high potassium (KCl 40 mM). A) The vehicle of estrogens, ethanol (ETOH 0.1%), did not significantly modify KCl-induced contraction (P > 0.05) whereas this tonic contraction was significantly inhibited by 17α- or 17β-E2 and this response was also significantly different from the vehicle control (P < 0.0005). The black circles represent the time of washout. B) Comparison of inhibitory effect at equimolar concentration (200 μM) of 17α- and 17β-E2 on spontaneous and KCl(40 mM)-induced contraction. The student's t test demonstrated that the relaxing efficacy of 17α- and 17β-E2 was not significantly different (P > 0.05) on spontaneous or KCl-induced contraction. The plotted values represent the mean ± SEM of six independent experiments.