首页 | 本学科首页   官方微博 | 高级检索  
     


Suppression of follicle wave emergence in cyclic ewes by supraphysiologic concentrations of estradiol-17beta and induction with a physiologic dose of exogenous ovine follicle-stimulating hormone
Authors:Barrett David M W  Bartlewski Pawel M  Duggavathi Rajesha  Davies Kate L  Rawlings Norman C
Affiliation:Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5B4.
Abstract:
Follicle waves are preceded by follicle-stimulating hormone (FSH) peaks in ewes. The purpose of the present study was to see whether estradiol implant treatment would block FSH peaks to create a model in which the effect of the timing and mode of FSH peaks could be studied by ovine FSH (oFSH) injection. In Experiment 1, 10 ewes received estradiol-17beta implants on Day 4 after ovulation (Day 0, day of ovulation); five ewes received large implants, and five ewes received small implants. Five control ewes received empty implants. In Experiment 2, 12 ewes received large implants on Day 4. On Day 9, six ewes received oFSH twice, 8 h apart (0.5 microg/kg; s.c.). Implants were left in place for 10 days in both experiments. In both studies, ovarian ultrasonography and blood sampling was done daily. In Experiment 1, estradiol concentrations were significantly higher in ewes with large implants (10.4 +/- 0.7 pg/ml) compared with controls (3.9 +/- 0.7 pg/ml) and ewes with small implants (5.4 +/- 0.7 pg/ml; P < 0.001). A significant reduction was found in mean FSH peak concentration (31%; P < 0.05) and FSH peak amplitude (45%; P < 0.05) in ewes with large implants compared with controls. Mean and basal FSH concentrations were unaffected by the large implants. The large implants halted follicle-wave emergence between Day 0 and 8 after implant insertion. The small follicle pool (2-3 mm in diameter) was unaffected by the large implants. When oFSH was injected into ewes with large implants, a follicle wave emerged 1.5 +/- 0.5 days after injection; however, in ewes given saline alone, a follicle wave emerged 4.8 +/- 0.8 days after injection (P < 0.01). We concluded that truncation of FSH peaks by estradiol implants prevented follicle-wave emergence, but injection of physiologic concentrations of oFSH reinitiated follicle-wave emergence.
Keywords:
本文献已被 PubMed 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号