DEVELOPMENT OF OVARIAN AUTOGRAFTS ON THE GREATER OMENTUM OF OVARIECTOMIZED AND HEMI-OVARIECTOMIZED RATS UNITED BY COELIO-ANASTOMOSIS

ABSTRACT Ovariectomized and hemi-ovariectomized 3 week old non-littermate rats bearing ovarian implants on the greater omentum were parabiosed by coelio-anastomosis. Controls consisted of 67 spayed and 58 hemi-spayed single animals with similar ovarian implants. To each pair of parabionts an older female rat served as »nurse« keeping them in relatively good health; the mortality rate, nevertheless reached about 20 %. After one month 15 parabiotic pairs and all the control animals were killed. In the hemi-spayed parabionts the mean weights of the uteri and ovaries in situ were significantly higher than in single control animals while the rise in the mean pituitary weight was not significant. The mean weight of the implants was the same as in the control rats. In the spayed parabionts the mean weights of the uteri and pituitaries were significantly higher than in single control rats. The small decrease in the mean weight of the implants was not statistically significant. The results obtained show that oestrogens passed from the hemi-spayed to the spayed animals probably causing inter alia, a decrease in gonadotrophin production and release. The amount of gonadotrophins passing from the spayed to the hemi-spayed partners was, however, sufficient to influence the development of the ovaries and uteri. In contrast, the development of the ovarian implants was not stimulated. This discrepancy confirms the assumption that the ovary in situ produces a substance which inhibits gonadotrophic activity at the level of the implant.