INDUCTION AND INHIBITION OF LABOUR IN THE RABBIT

Abstract

The rabbit has been used extensively for experimental studies on the hormonal control of pregnancy, and consequently a considerable knowledge of the effect of various hormones in this animal has been collected. In 1926 Knaus demonstrated that the sensitivity of the rabbit uterus to pituitary extract increased with advancing gestation. Labour could be induced from the 29th day to term (32nd day), the necessary dose of pituitary extract decreasing towards the day of spontaneous delivery. Between the 17th and 29th day pituitary extract never induced abortion directly, but prolonged administration caused the death of the foetuses which were then expelled from the uterus some days later. In the period from conception to the 17th day pregnancy was not disturbed by pituitary extract whatever reasonable quantity was administered. Allen & Corner (1930) found that pregnancy could be maintained in castrated rabbits by the administration of extracts of corpora lutea from swine.