Linked Life Data

8822321

Source:http://linkedlifedata.com/resource/pubmed/id/8822321

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1996-11-14
pubmed:abstractText
Expression of gonadotropin-releasing hormone (GnRH) gene in the hypothalamus of female rats was studied by the quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. During the estrous cycle, the GnRH mRNA level did not change from diestrus I to II, and then increased with a peak at 1100 h on proestrus. In the afternoon of proestrus, GnRH mRNA decreased rapidly with a nadir at 1600 h, and thereafter increased again and reached a peak at 1100 h on estrus. Since hypothalamic GnRH mRNA was found to be increased by subcutaneous implantation of estradiol-containing silastic tubing in ovariectomized rats, the peak of GnRH gene expression in the proestrous morning might be due to an increase in circulating estrogen in this phase of the estrous cycle. The surge of luteinizing hormone in the proestrous afternoon and the subsequent increase in GnRH mRNA were completely blocked by the injection of MK801, an antagonist for NMDA receptors, suggesting that the excitation of GnRH neurons leads to an increase in GnRH gene expression. This was further supported by the in vitro observation that high K(+)-induced membrane depolarization markedly increased GnRH mRNA in hypothalamic slices. This increase in GnRH mRNA due to neuronal excitation does not seem to require newly synthesized proteins because anisomycin, a protein synthesis inhibitor at the level of translation, did not affect GnRH gene expression. These results suggest that the hypothalamic GnRH mRNA level reached two peaks during the rat estrous cycle, i.e., in proestrous morning and estrous morning, and that estrogen and GnRH neuronal excitation play pivotal roles in regulating GnRH gene expression.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0918-8959
pubmed:author
pubmed:issnType
Print
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
789-796
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Hypothalamic gonadotropin-releasing hormone gene expression during rat estrous cycle.
pubmed:affiliation
Department of Veterinary Physiology, University of Tokyo, Japan.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't