Evaluation of the maternal and neonatal effects of the oxytocin antagonist, atosiban, in a cross-fostering study in rats.

摘要

The purpose of this cross-fostering study was to investigate neonatal survival following exposure of pregnant rats to atosiban (1-deamino-2-d-Tyr(OEt)-4-Thr-8-Orn-oxytocin), an oxytocin antagonist. Atosiban was administered subcutaneously from days 15 to 20 of gestation at 300mg/kg/day, and controls received vehicle alone. Parturition was observed at 30min intervals throughout the period that births were occurring. There was no effect of treatment on number of pups born or neonatal viability. Within 1h of birth, litter size was standardised to five males and five females, followed immediately by cross-fostering either between or within groups. Offspring from treated mothers reared by control mothers had normal survival and weight gain. There was poor survival and weight gain in offspring from control mothers reared by treated mothers. There was clear evidence that lactation was impaired in the treated females, leading to the conclusion that poor neonatal survival in offspring reared by treated mothers was attributable to a failure of milk let-down.