Ovary transplanted to spleen in rats: the effect of unilateral castration, pregnancy, and subsequent castration.

Abstract

Summary A regular sequence of events occurs after one ovary has been transplanted into the spleen of a castrate rat. After the initial inflammatory reaction has subsided, there is a constant development of new follicles which luteinize. These corpora lutea do not involute, and from them, after 5 months or more, a luteoma appears. Subsequently, a granulosa-cell tumor may replace the luteoma. If an ovary is transplanted into the spleen of a unilaterally castrate rat, the intrasplenic ovary at rophies. The growth potentialities of this atrophic intrasplenic ovary become evident as soon as the normal ovary is excised. The effect of pregnancy on the intrasplenic ovary of unilateral castrates is to produce active follicular growth usually without the formation of corpora lutea. Following termination of the pregnancy, the intrasplenic ovary atrophies; however, simultaneous termination of the pregnancy and castration produce active growth in the intrasplenic ovary. The changes that take place in the ovary transplanted to the spleen of a unilaterally castrated rat were examined in 30 animals at intervals varying from 1 to 465 days. The transplant undergoes a progressive decrease in size, rarely contains corpora lutea, the number of follicles decreases, and the stroma contains cords of large cells that resemble thecal cells. Despite this atrophy, if the normally situated ovary is removed, the transplant is capable of growth characterized by the continuous formation of many follicles which undergo luteinization. These findings were demonstrated in thirteen animals. The effect of pregnancy on the intrasplenic ovary in the unilateral castrate was examined in 22 animals. In twelve that were sacrificed at the time of delivery or the next day, the transplant revealed many small follicles; in only one was there a corpus luteum. The remainder were examined at intervals after the delivery, and the transplant decreased in size, contained fewer and smaller follicles, and in three there were remnants of one or two corpora lutea. Again, removal of the normally castrated ovary at the termination of pregnancy permitted the intrasplenic ovary to undergo a somewhat accentuated follicular and luteal growth.