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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2-3
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pubmed:dateCreated |
1994-8-16
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pubmed:abstractText |
A large body of evidence suggests multiple forms of 17 beta-hydroxysteroid oxidoreductase (17-HOR) regulate estrogen and androgen levels within gonadal and peripheral tissues. Two kinetically-differing 17-HOR activities have been detected in placental homogenates. 17-HOR type 1, found mainly in the cytosol, is highly reactive with estradiol-17 beta (E2) and estrone (E1) but not testosterone (T) (high E2/T activity ratio). Microsomal 17-HOR type 2 is reactive with both E2 and T (low E2/T activity ratio). In this study, 17-HOR activity of cytosol and microsomes from term placenta, ovarian stroma and granulosa-luteal cells was assayed under conditions which specifically differentiate between the two forms of the enzyme. Placenta had the highest activity with either E2 or T in both cytosol and microsomes and stroma the lowest. The highest specific activity with E2 and E1 was cytosolic in all samples. The highest specific activity with T was microsomal in placenta and ovarian stroma. E2/E1 activity ratios were comparable for cytosol and microsomes while E2/T activity ratios were comparable for placenta and stroma, but markedly elevated in granulosa-luteal (G-L) cell cytosol and microsomes. The results indicate trophoblast and ovarian stroma have more 17-HOR type 2 relative to type 1. G-L cells, in contrast, are relatively enriched in 17-HOR type 1 and thus have a greater capacity for net conversion of E1 to E2 under physiologic conditions. These differences may contribute to increasing serum and follicular fluid E2/E1 ratios during development of the dominant follicle.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
|
pubmed:month |
Jun
|
pubmed:issn |
0960-0760
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pubmed:author | |
pubmed:issnType |
Print
|
pubmed:volume |
49
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pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
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pubmed:pagination |
183-9
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:8031715-17-Hydroxysteroid Dehydrogenases,
pubmed-meshheading:8031715-Cytosol,
pubmed-meshheading:8031715-Estradiol,
pubmed-meshheading:8031715-Estrone,
pubmed-meshheading:8031715-Female,
pubmed-meshheading:8031715-Granulosa Cells,
pubmed-meshheading:8031715-Humans,
pubmed-meshheading:8031715-Hydrogen-Ion Concentration,
pubmed-meshheading:8031715-Kinetics,
pubmed-meshheading:8031715-Luteal Cells,
pubmed-meshheading:8031715-Microsomes,
pubmed-meshheading:8031715-Ovary,
pubmed-meshheading:8031715-Placenta,
pubmed-meshheading:8031715-Pregnancy,
pubmed-meshheading:8031715-Substrate Specificity,
pubmed-meshheading:8031715-Testosterone
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pubmed:year |
1994
|
pubmed:articleTitle |
A comparison of 17 beta-hydroxysteroid oxidoreductase type 1 and type 2 activity of cytosol and microsomes from human term placenta, ovarian stroma and granulosa-luteal cells.
|
pubmed:affiliation |
Department of Obstetrics and Gynecology, Ramsey Clinic, St. Paul, MN.
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pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, Non-U.S. Gov't
|