title: Effect of oxytocin on concentrations of prostaglandin H synthase-2 mRNA in ovine endometrial tissue in vivo.
abstract: Oxytocin is an acute stimulus of prostaglandin (PG) F2alpha secretion from the ovine uterine endometrium. The high level of PGF2alpha secretion induced by oxytocin and the short half-life of the prostaglandin synthase-2 (PGHS-2) enzyme implies that synthesis of PGHS-2 may be essential at this time. The objective of this study was to determine if the increase in PGF2alpha secretion induced by oxytocin is associated with an increase in PGHS-2 mRNA. In experiment 1, oxytocin induced a rapid increase in serum concentration of 13,14-dihydro-15-keto-prostaglandin F2alpha (the stable metabolite of PGF2alpha; PGFM) that was detected within 7.5 min (P < 0.05) and peaked at 25 min post injection. This was associated with an unusually rapid increase in the concentration of PGHS-2 mRNA at 25 min post oxytocin injection (P < 0.05). Endometrial concentrations of PGHS-2 mRNA returned to basal levels at 90 min post injection. Experiment 2 was conducted to further characterize the time course of induction of PGHS-2 mRNA following oxytocin administration. Oxytocin induced a rapid increase in serum concentrations of PGFM. As in experiment 1, an increase in concentrations of PGHS-2 mRNA was detected at 25 min after oxytocin (P = 0.06). Concentrations of PGHS-2 mRNA were intermediate at 40 min and returned to basal levels at 60 min post injection. Thus, there is a rapid increase in endometrial concentrations of PGHS-2 mRNA following oxytocin stimulation of PGF2alpha secretion. This increase in PGHS-2 mRNA may be required to maintain PGHS-2 enzyme levels during pulsatile secretion of PGF2alpha at luteolysis.
authors.affiliation: Department of Animal Sciences and Center for Membrane Sciences, University of Kentucky, Lexington 40546-0215, USA.
authors.forename: P D
authors.initials: PD
authors.lastname: Burns
authors.forename: S J
authors.initials: SJ
authors.lastname: Tsai
authors.forename: M C
authors.initials: MC
authors.lastname: Wiltbank
authors.forename: S H
authors.initials: SH
authors.lastname: Hayes
authors.forename: G A
authors.initials: GA
authors.lastname: Graf
authors.forename: W J
authors.initials: WJ
authors.lastname: Silvia
mesh_terms: D000818:Animals; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood; D004717:Endometrium / Q000187:drug effects* / Q000378:metabolism*; D005260:Female; D007527:Isoenzymes / Q000235:genetics*; D009994:Osmolar Concentration; D010121:Oxytocin / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D012756:Sheep
chemical_list: D007527:Isoenzymes; D012333:RNA, Messenger; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; D010121:Oxytocin; D015237:Dinoprost; D011451:Prostaglandin-Endoperoxide Synthases