Linked Life Data

16825323

Source:http://linkedlifedata.com/resource/pubmed/id/16825323

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2006-9-18
pubmed:abstractText
Follicular production of prostaglandins (PGs) is essential for ovulation, but the factors mediating gonadotropin-induced secretion of PGE and PGF(2alpha) remain largely unknown. We tested the hypothesis that gonadotropin-induced changes in progesterone and its receptor (PR) mediate the increase in periovulatory PGs. Heifers were treated with PGF(2alpha) and GnRH to induce luteolysis and the LH/FSH surge (ovulation occurs approximately 30 h after GnRH). Because there are two increases in intrafollicular progesterone/PR mRNA during the bovine periovulatory period, we first examined the temporal pattern of PG production by follicles collected at 0, 3.5, 6, 12, 18, and 24 h after GnRH. Although PGs did not increase in the follicular fluid until 24 h after GnRH, acute secretion of PGs by follicle wall (theca + granulosa cells) was initiated by 18 h and had increased manyfold by 24 h after GnRH. In vitro, FSH and LH induced dramatic transient increases in PG production by follicle wall and granulosa, but not theca, cells isolated from preovulatory follicles (0 h after GnRH). PG accumulation peaked on d 2 of culture, mimicking the secretion pattern after a gonadotropin surge in vivo. In cultures of follicle wall and granulosa cells, the PR antagonist mifepristone (MIFE, 1 microm) inhibited LH-induced PG secretion and the progestin medroxyprogesterone acetate (1 or 10 microm), but not the glucocorticoid dexamethasone (1 or 10 microm), overcame the effect of MIFE on PGs. Semiquantitative RT-PCR revealed that MIFE inhibited LH-induced expression of cyclooxygenase-2 mRNA in granulosa cells in vitro. Again, treatment with medroxyprogesterone acetate overcame the effect of MIFE. Together these results provide strong evidence that periovulatory increases in cyclooxygenase-2 mRNA, PGE, and PGF(2alpha) are mediated by gonadotropin-induced increases in progesterone/PR, indicating that in some species there is an important functional relationship between these pathways in the ovulatory cascade.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
147
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4713-22
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:16825323-Animals, pubmed-meshheading:16825323-Cattle, pubmed-meshheading:16825323-Cyclooxygenase 2, pubmed-meshheading:16825323-Dinoprost, pubmed-meshheading:16825323-Female, pubmed-meshheading:16825323-Follicle Stimulating Hormone, pubmed-meshheading:16825323-Gonadotropin-Releasing Hormone, pubmed-meshheading:16825323-Gonadotropins, pubmed-meshheading:16825323-Granulosa Cells, pubmed-meshheading:16825323-Luteinizing Hormone, pubmed-meshheading:16825323-Ovarian Follicle, pubmed-meshheading:16825323-Ovulation, pubmed-meshheading:16825323-Prostaglandins E, pubmed-meshheading:16825323-RNA, Messenger, pubmed-meshheading:16825323-Radioimmunoassay, pubmed-meshheading:16825323-Receptors, Progesterone, pubmed-meshheading:16825323-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:16825323-Theca Cells
pubmed:year
2006
pubmed:articleTitle
Gonadotropin-induced expression of messenger ribonucleic acid for cyclooxygenase-2 and production of prostaglandins E and F2alpha in bovine preovulatory follicles are regulated by the progesterone receptor.
pubmed:affiliation
Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural