Oxytocin and Oxytocin Antagonist Metabolism in the Plasma of Pregnant Women. |
Tae Hun An, Sok Cheon Pak, Tae Gyu Ahn |
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. |
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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. |
Key Words:
Oxytocin, Oxytocin antagonist, Uterus, Pregnant women, Preterm labor |
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