Linked Life Data

14636178

Source:http://linkedlifedata.com/resource/pubmed/id/14636178

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2003-11-25
pubmed:abstractText
Oestradiol exerts negative- and positive-feedback actions on luteinizing hormone (LH) secretion by modulating gonadotropin-releasing hormone (GnRH) release. Furthermore, a chronic increase in circulating oestradiol in either young ovariectomized (OVX) rats, or in middle-aged persistent oestrous (PE) rats, causes a gradual attenuation of LH surges until the positive-feedback action of oestradiol disappears. Based on these findings, and on the equivocal evidence regarding a direct action of oestradiol on GnRH neurones, we tested the hypothesis that chronic oestradiol abolishes LH surges by decreasing the proportion of GnRH neurones containing oestrogen receptor (ER)alpha or beta. Regularly cycling rats were ovariectomized, and half immediately received oestradiol. Three days, or 2 or 4 weeks later, rats were perfused at 18.00 h, and GnRH was colocalized with ERalpha or ERbeta by immunocytochemistry. ERbeta was expressed in 76% of GnRH neurones, whereas virtually no GnRH cells were immunopositive for ERalpha. The proportion of GnRH cells expressing ERalpha or beta in OVX rats was not altered by oestradiol or time after OVX, and this was the case regardless of their medial to lateral, or rostral to caudal location. The results indicate that the mechanisms for the positive-feedback action of oestradiol, and the loss of LH surges in OVX rats after chronic oestradiol, are not mediated by changes in the proportion of oestrogen-receptor containing GnRH neurones.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0953-8194
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1164-70
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Oestrogen receptor-alpha and -beta immunoreactivity in gonadotropin-releasing hormone neurones after ovariectomy and chronic exposure to oestradiol.
pubmed:affiliation
Department of Physiology, University of Kentucky, Lexington, KY, USA. sjlegan@uky.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.