A Search for Neurological Mechanisms in Ovulation. 20

There is no doubt that the nervous system is involved in producing the ovulation which follows copulation in the rabbit. The observations here presented represent one phase of our attack upon this problem.

Ascheim and Zondek 1 found that a substance (Prolan) in the urine of pregnant women produces effects similar to the sex hormone in the anterior lobe of the hypophysis. Friedman 2 induced ovulation in the rabbit by the intravenous injection of the urine of pregnant women. The utility of this reaction depends upon the fact that ovulation does not occur spontaneously in the rabbit (Heape, 3 Ancel and Bouin, 4 Hammond and Marshall 5 ). We have utilized the Friedman phenomenon to produce ovulation at will in the rabbit. Evidence has been presented that prolan and the sex hormone from the anterior lobe of the hypophysis are not identical (Parkes and Hill, 6 Reichert, Pencharz, Simpson, Meyer and Evans, 7 Evans, Meyer and Simpson, 8 Wallen-Lawrence and Van Dyke, 9 and Loeb 10 ). We have been concerned in finding out whether or not any of the efferent pathways from the central nervous system are involved in the ovulation that follows the injection of pregnancy urine into the rabbit. Although ovulation has occurred in transplanted ovaries in many species including man (Knauer, 11 Grigorieff, 12 and Frank 13 ), this is the first study in the rabbit of induction of ovulation in ovaries completely isolated from the influence of the central nervous system.

Virgin rabbits, weighing 2 to 3 kilos, were isolated in individual cages for 3 weeks. Ovulation was induced in each case by the injection of 8 to 10 cc. of the urine of pregnant women, and the ovaries were examined approximately 20 hours following the injection. An autopsy was done to control the experimental procedures in each of the experiments.