On Ovarian Regeneration in the Albino Rat.

Abstract

Numerous cytological papers on germ cell origin have led to the view that the primordial germ cells are not the ancestors of the functional germ cells, although work is not lacking in which the older view is upheld that germ cells form a continuous stream throughout the individual life cycle and from generation to generation.

Davenport, 1 spaying mice, found that, after a lapse of from 8 to 45 weeks, regeneration of the ovary occurred in 64% of his animals. Complete removal of the ovary was claimed, but cytological evidence was not secured in support of this. Macroscopic examination of masses of tissue at or near the site of the operation was the criterion for regeneration of the ovary. Haterius 2 secured 4 cases of regenerated ovarian tissue in mice out of 76 operations, and attributed these to incomplete ovarian extirpation. Parkes, Fielding and Brambell 3 had 121 cases of double ovariotomized mice. After ovariotomy the oestrous cycle (vaginal smear method) ceased. But in 11 cases spontanoeus oestrus subsequently occurred, and this was taken to indicate regenerated ovarian tissue. In 8 of these 11 cases the presence of new ovarian tissue was demonstrated histologically.

We are able to add data of a similar nature from the albino rat. Both ovaries were removed from 105 rats and each ovary preserved for sectioning. The animals ranged in age from 10 to 200 days at time of operation. The period allowed for regeneration ranged from 90 to 180 days. There were 8 cases of ovarian regeneration as determined by sectioning the regenerated masses of tissue. The 8 original ovaries removed from these sites of regeneration were then sectioned to determine whether the whole ovary had been removed.