Linked Life Data

3304436

Source:http://linkedlifedata.com/resource/pubmed/id/3304436

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1987-10-7
pubmed:abstractText
The long-term negative feedback effects of sustained elevations in circulating estradiol and progesterone on the pulsatile secretion of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) were evaluated in the ewe following ovariectomy during the mid-late anestrous and early breeding seasons. GnRH secretion was monitored in serial samples of hypophyseal portal blood. Steroids were administered from the time of ovariectomy by s.c. Silastic implants, which maintained plasma concentrations of estradiol and progesterone at levels resembling those that circulate during the mid-luteal phase of the estrous cycle; control ewes did not receive steroidal replacement. Analysis of hormonal pulse patterns in serial samples during 6-h periods on Days 8-10 after ovariectomy disclosed discrete, concurrent pulses of GnRH in hypothalamo-hypophyseal portal blood and LH in peripheral blood of untreated ovariectomized ewes. These pulses occurred every 97 min on the average. Treatment with either estradiol or progesterone greatly diminished or abolished detectable pulsatile secretion of GnRH and LH, infrequent pulses being evident in only 3 of 19 steroid-treated ewes. No major seasonal difference was observed in GnRH or LH pulse patterns in any group of ewes. Our findings in the ovariectomized ewe provide direct support for the conclusion that the negative-feedback effects of estradiol and progesterone on gonadotropin secretion in the ewe include an action on the brain and a consequent inhibition of pulsatile GnRH secretion.
pubmed:grant
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
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1207-18
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Steroid feedback inhibition of pulsatile secretion of gonadotropin-releasing hormone in the ewe.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't