Ovarian Follicular Atresia and Follicular Estradiol-17β after Unilateral Ovariectomy in Pregnant Gilts

Abstract

Twenty-three crossbred gilts were assigned at random to four groups and were treated during pregnancy as follows: C-4 (sham surgery on day 4), Ov-4 (unilateral ovariectomy on day 4), C-15 (sham surgery on day 15), and Ov-15 (unilateral ovariectomy on day 15). Follicular atresia, measured on day 27 of verified pregnancy by the percentage of milky follicles was not altered by unilateral ovariectomy on day 4 or day 15. Follicular compensation appeared to result from increased growth rate of follicles to a larger size than in controls. Follicular fluid estradiol-17β content in the remaining ovary of gilts unilaterally ovariectomized on day 4 or day 15 was more than double the content of a single ovary of intact gilts. The increased content was due to increased follicle size as unilateral ovariectomy did not affect estradiol-17β concentration in follicular fluid. The ovarian content of estradiol-17β in the unilaterally ovariectomized gilts was significantly correlated with the concentration of estrogen in the serum. These data suggest that the steroid synthesizing activity of follicles increases with the increase in follicle size which occurs after unilateral ovariectomy. Copyright © 1976. American Society of Animal Science . Copyright 1976 by American Society of Animal Science