On the occurrence of the œstrous cycle after X-ray sterilisation part II.—Irradiation at or before birth

Abstract

The first paper of this series dealt with the effects on the œstrous cycle of X-ray sterilisation of the young female mouse at 3 weeks old. The conclusions arrived at were briefly as follows :— (1) Adequate exposure to X-rays causes disintegration of the Graafian follicles, and when puberty is subsequently reached the ovary contains no organised follicles, and in most cases no luteal or other tissue recognisable as being of follicular derivation. (2) In spite of this elimination of the cyclic structures of the ovary, the accessory organs of the majority of the animals experienced the normal periodic changes which constitute the œstrous cycle. (3) These results made it quite clear that neither Graafian follicles nor corpora lutea are necessarily essential for the periodic occurrence of œstrus, but no satisfactory explanation was arrived at of the means whereby the cyclic action of the œstrous-producing hormone is regulated. Since these results were entirely opposed to what has usually been thought of the regulation of the œstrous cycle, it seemed desirable that the same type of experiment should be repeated under somewhat different conditions.