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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1987-3-4
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pubmed:abstractText |
The cytosolic concentration of free Ca2+ ([Ca2+]i) in normal rat pituitary cells separated by centrifugal elutriation was monitored with the fluorescent Ca2+ indicator Quin 2. GnRH (10(-7) M) induced a rapid rise (6-8 sec) in the gonadotroph's [Ca2+]i, followed by a plateau phase of prolonged elevated [Ca2+]i which lasted about 15 min. The stimulatory effect of GnRH was dose dependent, with an ED50 of 10(-9) M, and was blocked by the potent antagonist [Dp-Glu1,pclPhe2,DTrp3.6]GnRH. GnRH elevated [Ca2+]i only in gonadotroph-enriched cell fractions, whereas TRH and GH-releasing factor (GRF) elevated [Ca2+]i in mammotroph- and somatotroph-enriched cells fractions, respectively. A rapid increase (first phase) in [Ca2+]i induced by GnRH was observed in Ca2+-free medium containing EGTA, but this rapid phase was terminated within 2 min. Readdition of Ca2+ to the medium induced a second slower rise in [Ca2+]i (plateau phase). Addition of K+ caused a rapid rise in [Ca2+]i, which was dependent on extracellular Ca2+, but was not affected by prior stimulation with GnRH. On the other hand, stimulation of gonadotroph's [Ca2+]i response by GnRH desensitized the cells to a subsequent GnRH challenge within the time frame studied. These findings indicate an elevation of [Ca2+]i induced by GnRH, TRH, and GRF in their respective separated target cells in the rat pituitary. The rise in [Ca2+]i in GnRH-stimulated gonadotrophs originates partly from intracellular Ca2+ pools and partly from influx of Ca2+ across the cell membrane.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
AIM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Aminoquinolines,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Fluorescent Dyes,
http://linkedlifedata.com/resource/pubmed/chemical/Gonadotropin-Releasing Hormone,
http://linkedlifedata.com/resource/pubmed/chemical/Quin2
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pubmed:status |
MEDLINE
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pubmed:month |
Feb
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pubmed:issn |
0013-7227
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
120
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
497-503
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:3542505-Aminoquinolines,
pubmed-meshheading:3542505-Animals,
pubmed-meshheading:3542505-Calcium,
pubmed-meshheading:3542505-Cell Separation,
pubmed-meshheading:3542505-Centrifugation,
pubmed-meshheading:3542505-Cytosol,
pubmed-meshheading:3542505-Female,
pubmed-meshheading:3542505-Fluorescent Dyes,
pubmed-meshheading:3542505-Gonadotropin-Releasing Hormone,
pubmed-meshheading:3542505-Kinetics,
pubmed-meshheading:3542505-Pituitary Gland, Anterior,
pubmed-meshheading:3542505-Rats,
pubmed-meshheading:3542505-Rats, Inbred Strains
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pubmed:year |
1987
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pubmed:articleTitle |
Cytosolic free calcium levels in cultured pituitary cells separated by centrifugal elutriation: effect of gonadotropin-releasing hormone.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, Non-U.S. Gov't
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