Follicle diameters and hormone concentrations in the development of single versus double ovulations in mares

被引:25
作者
Ginther, O. J. [1 ,2 ]
Gastal, E. L. [1 ]
Rodrigues, B. L. [1 ]
Gastal, M. O. [2 ]
Beg, M. A. [1 ]
机构
[1] Univ Wisconsin, Sch Vet Med, Dept Pathobiol Sci, Madison, WI 53706 USA
[2] Eutheria Fdn, Cross Plains, WI 53528 USA
关键词
double ovulation; estradiol; follicles; gonadotropins; mares;
D O I
10.1016/j.theriogenology.2007.11.004
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
Relationships between double ovulations and plasma hormone concentrations were compared between 18 single ovulating and 6 double ovulating mares. The study began when the first follicle reached >= 30 mm, and ultrasound scanning and blood sampling were done every 12 h to Day 3 (ovulation = Day 0). Data were analyzed for 2.5 d after the largest follicle was >= 30 mm and after Day -2.5 to encompass the mean 5-d interval between a >= 30 mm follicle and Day 0. During the 2.5 d after >= 30 mm, the increasing diameter of the largest follicle was less pronounced and plasma FSH concentrations were lower (approached significance) in the double ovulators than in the single ovulators. By Day -2.5, the largest follicle was smaller (P < 0.01) and plasma FSH was lower (P < 0.04) in the double ovulators. Plasma estradiol concentrations were higher (P < 0.001) during the 2.5 d after >= 30 mm in the double ovulators and the correlation between estradiol and FSH was negative (r = -0.39, P < 0.0001). In double ovulators, compared to single ovulators, the largest follicle was smaller, FSH was lower and estradiol was higher on most occasions between Days -2.5 and -0.5 (P < 0.05), but plasma concentrations of LH and ir-inhibin were not significantly different. In conclusion, smaller preovulatory follicles in double ovulators were a response to lower FSH concentrations, due to higher estradiol concentrations from two preovulatory follicles; preovulatory differences in hormone concentrations between single and double ovulators were an effect rather than a cause of the double ovulations. (c) 2007 Elsevier Inc. All rights reserved.
引用
收藏
页码:583 / 590
页数:8
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