Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2-3
pubmed:dateCreated
1994-8-16
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.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0960-0760
pubmed:author
pubmed:issnType
Print
pubmed:volume
49
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
183-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
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.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't