Ovarian regeneration in the mouse after complete double ovariotomy

Abstract

The authors studied case histories of 121 double ovariot-omized mice. Detailed histories of 10 animals are given with a tabular summary. Most of the animals were used for the periodical testing of ovarian extract. Previous criteria of regeneration are criticized. Allen''s technique for daily examination of vaginal smears to determine oestrus furnished an accurate indication of regeneration by detecting oestrus after ovariotomy. Appearance of oestrous symptoms in ovariotomized mice which had not been injected invariably indicated ovarian regeneration. In some cases the regenerated ovaries were sterilized by X-irradiation. Ovaries removed at operation were preserved in all later cases. Serial sections of these demonstrated the completeness of removal. Diagnoses of intact animals were always checked by histological examination. Two reliable criteria of regeneration were found in mice which had been injected with oestrin: (a) appearance of oestrus at a time incompatible with injection; (b) appearance of a degree of cornification of vaginal epithelium not in keeping with what was to be expected of a given extract. Copulation did not prove an accurate index of regeneration. Regenerated ovarian tissue was never found on both sides; it was always close to the end of the Fallopian tube and completely surrounded by the fat body. Rete tubules were present in the hilum. There was frequently a peripheral band of cells resembling germinal epithelium. Oocytes, follicles, and corpora lutea were present in most cases. These cyclic structures could usually be correlated with the appearance of oestrus. No evidence of the origin of the regenerated ovarian tissue could be found. The possibility of ovarian regeneration in the human subject is briefly discussed.