The effect of 1-deamino-2-tyr(ethyl) oxytocin upon peri- and postnatal development of the rat: growth retardation of the offspring.

The effect of 1-deamino-2-tyr(ethyl) oxytocin (dEtOT) upon peri- and postnatal development of the rat was studied in two experiments when administered between day 15 of pregnancy and the day of parturition. The investigation showed that dEtOT did not affect the pups at birth, that dEtOT caused a dose-related growth retardation of the pups, that the growth inhibiting effect was directly correlated to the length of administration and that the growth inhibiting effect was more pronounced if dEtOT was given close to parturition than if it was given earlier in the pregnancy. In addition, the growth retardation was not due to an effect on the pups but to an effect on their mothers, probably related to inhibition of the emptying mechanisms of the mammary glands, meaning that the pups were insufficiently fed by their mothers immediately after birth.