Biology of reproduction
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Biology of reproduction · Aug 1997
Effect of the oxytocin antagonist atosiban (1-deamino-2-D-tyr(OET)-4-thr-8-orn-vasotocin/oxytocin) on nocturanl myometrial contractions, maternal cardiovascular function, transplacental passage, and fetal oxygenation in the pregnant baboon during the last third of gestation.
The oxytocin antagonist, atosiban (1-deamino-2-D-tyr(OET)-4-thr-8-orn-vasotocin/oxytocin), was infused i.v. to chronically instrumented pregnant baboons in the last third of pregnancy. Atosiban (6 microg/kg per min) inhibited myometrial electromyographic activity associated with spontaneous myometrial contractions that occurred around the onset of darkness between 134 and 162 days gestation (term 180 days gestation). The effect of atosiban on maternal heart rate was minimal. ⋯ Maternal atosiban clearance rates were 9.2-16.9 ml/kg per min. In conclusion, atosiban was very effective at inhibiting spontaneously occurring nocturnal myometrial contractions during the last third of gestation in the pregnant baboon. Although atosiban crosses the placenta relatively freely, there was no effect on fetal oxygenation.