Oxytocin modulates nitric oxide generation by human fetal membranes at term pregnancy.
OBJECTIVE
Nitric oxide (NO), an important mediator of the inflammatory response, is involved in several reproductive processes including pregnancy and labor. Uterus, placenta and fetal membranes are significant sources of NO. Presently, there is no information on factors regulating NO production by fetal membranes.


METHODS
Human fetal membranes at term gestation were cultured for 24 hr in the presence of oxytocin. The concentrations of NO metabolites nitrites in culture medium were determined by the Griess reaction. The presence of inducible nitric oxide synthase (iNOS) was determined by reverse transcriptase-polymerase chain reaction and Western blot.


RESULTS
Oxytocin increased nitrite release by fetal membranes. Messenger ribonucleic acid iNOS expression was also enhanced by oxytocin. These effects were more marked in tissues obtained after labor than before labor.


CONCLUSIONS
Oxytocin exerts an overall stimulatory effect on NO release by fetal membranes. This action might be of relevance in the biomolecular processes leading to parturition.
Ticconi
C
C
Department of Surgery, Section of Obstetrics and Gynecology, University of Rome Tor Vergata, Via di Tor Vergata, Rome, Italy. ticconi@med.uniroma2.it
Zicari
A
A
Realacci
M
M
Di Vito
M
M
Denora
P
P
Narcisi
M
M
Russo
M A
MA
Piccione
E
E
D019281:Dimerization; D005321:Extraembryonic Membranes / Q000187:drug effects* / Q000378:metabolism*; D005260:Female; D006801:Humans; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000378:metabolism; D010121:Oxytocin / Q000494:pharmacology*; D036801:Parturition / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D046509:Tissue Culture Techniques
D009573:Nitrites; D012333:RNA, Messenger; D009569:Nitric Oxide; D010121:Oxytocin; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II