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Predicate | Object |
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rdf:type | |
lifeskim:mentions |
umls-concept:C0010453,
umls-concept:C0014939,
umls-concept:C0023610,
umls-concept:C0030685,
umls-concept:C0032005,
umls-concept:C0036667,
umls-concept:C0205184,
umls-concept:C0229535,
umls-concept:C0312418,
umls-concept:C0391871,
umls-concept:C0680255,
umls-concept:C1280500,
umls-concept:C1283071,
umls-concept:C1555721,
umls-concept:C1706204,
umls-concept:C1709059,
umls-concept:C1963578
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pubmed:issue |
3
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pubmed:dateCreated |
1985-1-3
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pubmed:abstractText |
The sensitizing effect of oestrogens on GnRH-stimulated LH release was evaluated in pituitary cells from adult female rats, cultured for 2 days in the presence of 10(-13) to 10(-6) M concentrations of oestradiol and selected A- and D-ring modified oestrogens. With almost all steroids tested, bell-shaped dose-response curves with comparable LH-maxima but different ED max values were obtained for the LH response to a submaximal GnRH stimulus (5 X 10(-10) M). Maximal LH response to 5 X 10(-10) M GnRH were found at the following oestrogen concentrations: oestradiol and 4-hydroxyoestradiol = 10(-11) M; 2-methyloestradiol = 10(-9) M; 2-hydroxyoestradiol = 10(-8) M; with 4-methyloestradiol no significant maximum was observed. When cells were pretreated with 10(-13), 10(-11) and 10(-9) M oestradiol, or 4-hydroxyoestradiol, or 2-hydroxyoestradiol, and exposed to increasing concentrations of GnRH (10(-11) to 10(-7) M), an almost 10-fold decrease in the ED50 for GnRH was observed after pretreatment with 10(-11) M oestradiol and 4-hydroxyoestradiol. With 2-hydroxyoestradiol at this concentration, the sensitizing effect was much less pronounced. Increasing the steroid concentration to 10(-9) M slightly decreased the effect of oestradiol and 4-hydroxyoestradiol, whereas it increased the effect of 2-hydroxyoestradiol. Thus, at the target cell 4-hydroxyoestradiol has the same potency as oestradiol, while 2-hydroxyoestradiol is significantly less active. The sensitizing effect of oestradiol is only slightly decreased by the presence of a methyl group in position 2, but is markedly reduced by a methyl group in position 4. Our results also demonstrate the high sensitivity of the pituitary to oestrogen-induced enhancement of GnRH-stimulated gonadotrophin release, as well as the decrease of the positive effect at high oestrogen concentrations. The bell-shaped dose-response curves for oestrogen action should be taken into account when evaluating the effects of oestrogens and their derivatives upon gonadotrophin release from the pituitary gland.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Ascorbic Acid,
http://linkedlifedata.com/resource/pubmed/chemical/Estrogens,
http://linkedlifedata.com/resource/pubmed/chemical/Luteinizing Hormone,
http://linkedlifedata.com/resource/pubmed/chemical/Pituitary Hormone-Releasing Hormones,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Estrogen
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pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0001-5598
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
107
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
317-27
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:6391057-Animals,
pubmed-meshheading:6391057-Ascorbic Acid,
pubmed-meshheading:6391057-Cell Survival,
pubmed-meshheading:6391057-Cells, Cultured,
pubmed-meshheading:6391057-Dose-Response Relationship, Drug,
pubmed-meshheading:6391057-Estrogens,
pubmed-meshheading:6391057-Female,
pubmed-meshheading:6391057-Luteinizing Hormone,
pubmed-meshheading:6391057-Pituitary Gland,
pubmed-meshheading:6391057-Pituitary Hormone-Releasing Hormones,
pubmed-meshheading:6391057-Rats,
pubmed-meshheading:6391057-Rats, Inbred Strains,
pubmed-meshheading:6391057-Receptors, Estrogen
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pubmed:year |
1984
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pubmed:articleTitle |
Biphasic modulation of pituitary sensitivity to GnRH by oestrogens: the effects of A- and D-ring substitution on LH release in cultured pituitary cells.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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