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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2005-5-23
pubmed:abstractText
We designed three experiments to investigate the relationship between FSH peaks and ovarian follicular waves and to examine whether an endogenous rhythm of FSH peaks exists in sheep. In experiment 1, anestrous ewes were treated with ovine FSH (oFSH) or vehicle (6 ewes per group) at the expected time of an endogenous FSH peak, to double the FSH-peak amplitude in treated ewes. In experiment 2, anestrous ewes were treated with either oFSH or vehicle (6 ewes per group) at the expected time of two consecutive interpeak nadirs, such that the treated ewes had 5 FSH peaks in the time frame of 3 FSH peaks in control ewes. In experiment 3, to measure FSH concentrations, daily blood samples were collected from 5 cyclic ewes for a control period during the estrous cycle and then for three 17-day periods after ovariectomy. Daily blood samples were collected from another group of 8 ovariectomized ewes that were treated with estradiol-releasing implants and intravaginal progestogen sponges. Doubling the FSH-peak amplitude did not alter the characteristics of the following follicular wave. Increasing the frequency of FSH peaks stimulated the emergence of additional follicular waves, but did not alter the rhythmic occurrence of FSH peaks and follicular wave emergence. Endogenous follicular waves in oFSH-treated ewes emerged and grew in the presence of the growing largest follicle of the induced follicular waves. Finally, based on the observation of serum FSH concentrations in ovariectomized ewes, it appears that there exists an endogenous rhythm for peaks in daily serum FSH concentrations, which is, at least in part, independent of regulation by ovarian follicular growth patterns.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-3363
pubmed:author
pubmed:issnType
Print
pubmed:volume
72
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1466-74
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
The effect of the manipulation of follicle-stimulating hormone (FSH)-peak characteristics on follicular wave dynamics in sheep: does an ovarian-independent endogenous rhythm in FSH secretion exist?
pubmed:affiliation
Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5B4.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't