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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3
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pubmed:dateCreated |
1990-12-7
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pubmed:abstractText |
The progestin receptor antagonist RU 38486 (henceforth referred to as RU 486) was tested for facilitative effects on female receptive behavior in ovariectomized Long-Evans rats primed with 2 micrograms estradiol benzoate (EB). RU 486 (0, 0.5, 1.6, or 5.0 mg) was administered 48 hr after estrogen priming. The lordosis quotient (LQ) and lordosis score (LS) were assessed 4 hr after RU 486 administration in a standardized test consisting of a 10-mount test by a stimulus male. A significant dose effect was found by both LQ and LS, with those subjects receiving 5 mg of RU 486 being significantly more receptive than vehicle control animals. Thus RU 486 acted as a weak progestin agonist under testing conditions typical for assessment of progestin facilitation of female sexual behavior in rats. Low levels of proceptive behavior (hops and darts) were seen in a minority of the tests, and did not vary systematically as a function of the dose of RU 486 administered. We also examined the effects of RU 486 given before progesterone (P) on receptivity in a blocking paradigm and confirmed previous reports that the antagonist significantly attenuates facilitation of sexual behavior when given in combination with P. A progestin receptor assay of the cytosols of the hypothalamus-preoptic area in estrogen-primed female rats treated with 5 mg RU 486 revealed a significantly greater depletion of available cytosolic P receptors than when rats were treated with a similarly facilitating dose of P (100 micrograms). The results suggest a possible dual mode of action for RU 486--a weak, receptor-mediated agonistic effect on sexual behavior when given alone to estrogen-primed rats, and a competitive blocking effect on receptivity when administered with P.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Sep
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pubmed:issn |
0018-506X
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
24
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
301-10
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:2227845-Animals,
pubmed-meshheading:2227845-Brain,
pubmed-meshheading:2227845-Dose-Response Relationship, Drug,
pubmed-meshheading:2227845-Estradiol,
pubmed-meshheading:2227845-Female,
pubmed-meshheading:2227845-Injections, Subcutaneous,
pubmed-meshheading:2227845-Mifepristone,
pubmed-meshheading:2227845-Rats,
pubmed-meshheading:2227845-Receptors, Estrogen,
pubmed-meshheading:2227845-Receptors, Progesterone,
pubmed-meshheading:2227845-Sexual Behavior, Animal
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pubmed:year |
1990
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pubmed:articleTitle |
Facilitation of receptive behavior in estrogen-primed female rats by the anti-progestin, RU 486.
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pubmed:affiliation |
Department of Biological Sciences, Rutgers College, Rutgers University, Piscataway, New Jersey 08855-1059.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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