Evaluation of the maternal and neonatal effects of the oxytocin antagonist, atosiban, in a cross-fostering study in rats.
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 300 mg/kg/day, and controls received vehicle alone. Parturition was observed at 30 min intervals throughout the period that births were occurring. There was no effect of treatment on number of pups born or neonatal viability. Within 1 h 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.
McAnulty
Peter A
PA
Ferring Pharmaceuticals A/S, Ferring International Center, Kay Fiskers Plads 11, DK-2300 Copenhagen S, Denmark. peter.mcanulty@ferring.com
Burns
Lorna M
LM
D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight / Q000187:drug effects; D005260:Female; D006727:Hormone Antagonists / Q000008:administration & dosage / Q000633:toxicity*; D007279:Injections, Subcutaneous; D008098:Litter Size / Q000187:drug effects; D008136:Longevity / Q000187:drug effects; D008297:Male; D008431:Maternal-Fetal Exchange; D008893:Milk Ejection / Q000187:drug effects*; D010121:Oxytocin / Q000037:antagonists & inhibitors*; D036801:Parturition / Q000187:drug effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D014668:Vasotocin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000633:toxicity*; D015430:Weight Gain / Q000187:drug effects
D006727:Hormone Antagonists; C047046:atosiban; D010121:Oxytocin; D014668:Vasotocin