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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1999-6-3
pubmed:abstractText
Estrogen is an essential hormone for the LH surge and ovulation. The primary source of estrogen is from ovarian granulosa cells and in rats, estrogen, in turn, increases granulosa cell number and enhances FSH-stimulated gene expression in these cells. Thus, rat granulosa cells both respond to and synthesize estrogen. To further elucidate the mechanisms mediating the actions of estrogen in granulosa cells, we have identified and characterized the estrogen receptor-beta (ER-beta) subtype in rodent granulosa cells. ER-beta protein was localized to the nuclei of rat granulosa cells in preantral and antral follicles by immunocytochemistry, coincident with the location of ER-beta messenger RNA (mRNA). Immunoprecipitation and Western blot analysis using ER-beta specific antisera demonstrated a protein of approximately 60 kDa in granulosa cells prepared from PMSG-primed immature mice and estrogen-treated immature rats. Extracts from granulosa cells specifically bound an estrogen response element and the complex was recognized by antisera to ER-beta. A synthetic steroid estrogen radioligand, [125I]-17alpha-iodovinyl-11beta-methoxyestradiol ([125I]-VME2), bound to cytosolic granulosa cell preparations with high affinity (estimated K(D) value of 401 +/- 83 pM, and Bmax value of 102 +/- 9 fmol/mg protein). ER-beta protein levels rapidly declined following hCG treatment consistent with the reported decrease in binding activity and ER-beta mRNA levels by high levels of gonadotropins. Overall, we have demonstrated that 1) ER-beta protein is the dominant estrogen receptor subtype present in rodent granulosa cells, 2) this receptor is functional, and 3) it is regulated by ovulatory doses of gonadotropins. Thus, ER-beta is likely to be a mediator of estrogen action in rodent granulosa cells during follicular development.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
140
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2581-91
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Expression of estrogen receptor-beta protein in rodent ovary.
pubmed:affiliation
Molecular Biology Division, Women's Health Research Institute, Wyeth-Ayerst Research, Radnor, Pennsylvania 19087, USA. fitzpas2@war.wyeth.com
pubmed:publicationType
Journal Article