Korean J Obstet Gynecol.
2002 Jun;45(6):921-925.
Oxytocin and Oxytocin Antagonist Metabolism in the Plasma of Pregnant Women
- Affiliations
-
- 1Department of Anesthesiology College of Medicine, Chosun University, Kwangju, Korea.
- 2Hamilton College of Oriental Medicine, Hamilton, New Zealand.
- 3Department of Obstetrics and Gynecology, College of Medicine, Chosun University, Kwangju, Korea.
Abstract
OBJECTIVE
Oxytocin antagonists maybe useful in inhibiting the uterine contractions of preterm labor. One such compound is TT-235. The purpose of this study was to compare the resistance of TT-235 and oxytocin to enzymatic degradation by oxytocinase in pregnant human.
METHODS
Blood samples from pregnant women not in labor were incubated in vitro with known amounts of oxytocin and TT-235. Samples were collected at 0, 15, 30, 45 and 60 minute intervals for oxytocin analysis and at 0, 10, 60 and 360 minutes for TT-235 analysis. Oxytocin was analyzed by radioimmunoassay after extraction while TT-235 was analyzed by radioreceptor assay.
RESULTS
In human blood, oxytocin was readily metabolized with greater than 83% disappearance over the 60 minute incubation period. In contrast, TT-235 was stable up to 360 minutes of incubation.
CONCLUSION
This study suggests that: (1) blood from pregnant human does contain oxytocinase at least in vitro; and (2) TT-235 was resistant to enzymatic degradation by human blood, implying that this oxytocin antagonist may have prolonged activity in vivo in humans.