Abstract
The uterotonic activity of valyl-oxytocin was compared with that of synthetic oxytocin (Syntocinon) unit per unit in vitro and in vivo in 3-point matching assays in 30 women. The contractions of strips of human uterine muscle obtained by cesarean section were studied in vitro, and in vivo uterine motility was recorded with a guard-ring tacodynamometer a few hours postpartum. Valyl-oxytocin was 1.5 times more powerful than synthetic oxytocin in vitro, but 4.5 times more powerful in vivo.