Fig. 1.

A, The plasma estrogen concentration from ovariectomized rats (OVx) and 7–10 hr, 48 hr, and 7 d after a single injection of 10 or 50 μg of estrogen to ovariectomized rats. Data are pooled from animals used in the vmr and single-unit studies. *p < 0.05 compared with OVx or same dose of estrogen at 7 d. Data were analyzed with Kruskal–Wallis one-way ANOVA on ranks, followed by Dunn's multiple comparison test. B, The volume–pressure relationship of the distention balloon in ovariectomized and estrogen-treated rats. The volume was increased in 0.5 ml increments, and the corresponding pressure was recorded.