Linked Life Data

2458525

Source:http://linkedlifedata.com/resource/pubmed/id/2458525

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1988-10-18
pubmed:abstractText
Addition of GnRH to pituitary gonadotrophs preloaded with Quin 2 resulted in a rapid (approximately 8 s) mobilization of an ionomycin-sensitive intracellular Ca2+ pool. A second component of Ca2+ entry via voltage dependent channels contributed about 45% of the peak cytosolic free Ca2+ concentration ([Ca2+]i). Thereafter, influx of Ca2+ via voltage-sensitive and -insensitive channels is responsible for maintenance of elevated [Ca2+]i during the second phase of GnRH action. Addition of inositol 1,4,5-trisphosphate (IP3) to permeabilized pituitary cells resulted in a Ca2+ transient, released from a nonmitochondrial pool, which maintained ambient free Ca2+ concentration around 170 nM in an ATP-dependent mechanism. Successive stimulations of the cells with IP3 produced an attenuated response. Elevation of the gonadotroph [Ca2+]i by ionomycin, to levels equivalent to that induced by GnRH, resulted in LH release amounting to only 45% of the response to the neurohormone. Activation of the voltage-dependent Ca2+ channels by the dihydropyridine Ca2+-agonist [methyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine- 5-carboxylate (BAYK8644)] stimulated LH release, 36% of the GnRH (100 nM) response being reached by 10(-8) M of the drug, both [Ca2+]i elevation and GnRH-induced LH release were inhibited similarly (40-50%) by the dihydropyridine Ca2+-antagonist nifedipine. The results indicate that peak [Ca2+]i induced by GnRH in pituitary gonadotrophs is derived mainly from ionomycin-sensitive cellular stores most likely via IP3 formation.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0888-8809
pubmed:author
pubmed:issnType
Print
pubmed:volume
2
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
512-20
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Gonadotropin-releasing hormone-induced rise in cytosolic free Ca2+ levels: mobilization of cellular and extracellular Ca2+ pools and relationship to gonadotropin secretion.
pubmed:affiliation
Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't