Linked Life Data

1317786

Source:http://linkedlifedata.com/resource/pubmed/id/1317786

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1992-7-6
pubmed:abstractText
Two distinct isoforms of prostaglandin (PG) endoperoxide synthase (PGS) have been identified in rat ovarian tissues: rPGSi (mol wt, 70,000-72,000) is induced by FSH and LH in preovulatory follicles, whereas the other isoform (mol wt, 69,000) is not. Induction of rPGSi is associated with LH-stimulated increases in PG biosynthesis obligatory for ovulation. Because GnRH, like LH, can also stimulate the synthesis of PGs and ovulation in the rat, this study was undertaken to determine which isoform of PGS might be induced by GnRH, in what cell type, and by what intracellular pathways. Results show that GnRH at relatively low concentrations (10(-8)-10(-7) M) induced the same isoform of PGS (rPGSi) in the same cell type (preovulatory granulosa cells) and within the same 5- to 7-h time course as did LH. Unlike LH and FSH, GnRH did not cause a major increase in cAMP, nor did GnRH induce luteinization. The effects of GnRH on rPGSi in preovulatory follicles were not mimicked by known activators of protein kinase-C (phorbol myristate acetate, bryostatin, diacyglycerol, and (+/-)ionomycin). Epidermal growth factor (but not basic fibroblast growth factor or platelet-derived growth factor), which activates a receptor-associated tyrosine kinase, caused a small increase in rPGSi. Genistein, a selective inhibitor of tyrosine kinases, blocked GnRH and LH induction of rPGSi. Taken together these results suggest that the mechanisms by which GnRH and LH selectively induce rPGSi in granulosa cells of preovulatory follicles before ovulation may converge at some step within a cellular tyrosine kinase cascade. Furthermore, the mechanisms responsible for inducing rPGSi are distinct from those required for cellular luteinization.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
130
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3512-21
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:1317786-Animals, pubmed-meshheading:1317786-Cells, Cultured, pubmed-meshheading:1317786-Cyclic AMP, pubmed-meshheading:1317786-Dinoprost, pubmed-meshheading:1317786-Enzyme Induction, pubmed-meshheading:1317786-Epidermal Growth Factor, pubmed-meshheading:1317786-Estrogens, Non-Steroidal, pubmed-meshheading:1317786-Female, pubmed-meshheading:1317786-Genistein, pubmed-meshheading:1317786-Gonadotropin-Releasing Hormone, pubmed-meshheading:1317786-Isoflavones, pubmed-meshheading:1317786-Kinetics, pubmed-meshheading:1317786-Luteinizing Hormone, pubmed-meshheading:1317786-Ovarian Follicle, pubmed-meshheading:1317786-Progesterone, pubmed-meshheading:1317786-Prostaglandin-Endoperoxide Synthases, pubmed-meshheading:1317786-Radioimmunoassay, pubmed-meshheading:1317786-Rats, pubmed-meshheading:1317786-Sexual Maturation, pubmed-meshheading:1317786-Tetradecanoylphorbol Acetate
pubmed:year
1992
pubmed:articleTitle
Induction of prostaglandin H synthase in rat preovulatory follicles by gonadotropin-releasing hormone.
pubmed:affiliation
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.