| Immunohistochemical localization of prostaglandin H synthase in the sheep placenta from early pregnancy to term. | |
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MedLine Citation:
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PMID: 1786297 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Prostaglandin H synthase (PGHS) activity within intrauterine tissues is considered to catalyze a critical step in prostaglandin (PG) biosynthesis at parturition. In sheep, the placenta is a major site of PG production throughout pregnancy, but little information is available concerning the cells that are responsible. Therefore we determined the distribution of immunoreactive (IR-) PGHS in ovine placental tissue obtained at different times of pregnancy using immunohistochemical techniques. In placentomes from early pregnancy (Days 30-54), IR-PGHS was present in maternal epithelial syncytium, but was not detectable in trophoblast cells. Between Day 54 and Day 100, the number of cells that stained positive for PGHS declined in the maternal epithelial layer in the body of the placenta, but IR-PGHS was present in maternal epithelial cells overlying the vascular cones of the placental hemophagous zone. It was also present in the chorionic fibroblasts, but remained undetectable from all classes of trophoblast cells. IR-PGHS was first detectable in the trophoblastic epithelium by Day 114. Between Day 119 and term the trophoblast mononuclear epithelial cells were intensely immunopositive for PGHS, although immunonegative binucleate cells were present. The maternal epithelium was immunonegative except during the last 7-10 days of pregnancy when PGHS immunostaining appeared in both basal and apical regions of the placenta. Thus, the cellular localization of IR-PGHS changes during ovine pregnancy, from predominantly maternal during the first half of gestation to undetectable and then to predominantly trophoblastic between Day 114 and term, suggesting a gestation-dependent change in sites of PG production during ovine pregnancy. Appearance of IR-PGHS in the trophoblast precedes activation of the fetal hypothalamic-pituitary-adrenal axis, generally considered to provide the trigger to the onset of parturition in sheep, and would therefore appear to be regulated through alternative pathways or mechanisms. |
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Authors:
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D P Boshier; R A Jacobs; V K Han; W Smith; S C Riley; J R Challis |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Biology of reproduction Volume: 45 ISSN: 0006-3363 ISO Abbreviation: Biol. Reprod. Publication Date: 1991 Aug |
Date Detail:
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Created Date: 1992-03-20 Completed Date: 1992-03-20 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0207224 Medline TA: Biol Reprod Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 322-7 Citation Subset: IM |
Affiliation:
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MRC Group in Fetal and Neonatal Health and Development, Lawson Research Institute, London, Ontario, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Female Gestational Age Placenta / cytology, enzymology* Pregnancy Pregnancy Proteins / analysis* Pregnancy, Animal / metabolism* Prostaglandin-Endoperoxide Synthases / analysis* Sheep / metabolism* Trophoblasts / enzymology |
| Chemical | |
Reg. No./Substance:
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0/Pregnancy Proteins; EC 1.14.99.1/Prostaglandin-Endoperoxide Synthases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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