Age Changes in the Ovary 159 



This would confirm the general impression that ovarian 

 function in rodents is related to pituitary activity and not to 

 changes inherent in the ovaries themselves. 



Using CBA and A strain mice for the work, we are also 

 satisfied that a hybrid host can tolerate grafts of ovaries from 

 both parent strains. Of the six animals used all have shown 

 cestrous cycles and after mating have had vaginal plugs 

 and become pseudo-pregnant. So far two of them have 

 become pregnant. 



Before proceeding any further with the experiments it 

 will be necessary to establish more exactly the rate at which 

 the total number of follicles in the ovaries (both normal and 

 after transplantation) falls off as the mice get older. Only 

 when this information is available will one be able to say 

 anything with certainty about the interaction of the ageing 

 environment and the ageing ovary. 



Conclusion 



It is a far cry from the days of Voronoff and the expectation 

 that transplants of gonadal tissue would serve to rejuvenate 

 the senescent. It is now plain that such hopes, which rested 

 on the possible benefits of heterotransplantation, were bound 

 to be illusory. Today, even homotransplants of gonadal or of 

 endocrine tissue have no practical clinical value. In the 

 future, however, the method of transplantation may contri- 

 bute more as a research tool to the problem raised by the 

 ageing of tissues than it ever could ha^^e done in the past as a 

 form of treatment. 



Acknowledgement 



I am very grateful to Miss E. Holt for her assistance in carrying out 

 the experiments. 



REFERENCES 



Adams, C. E. (19;")8). In Ciba Foundation Symposium, Mammalian 



Germ Cells, p. 198. London: J. & A. Churchill, Ltd. 

 Amoroso, E. C, and Rowlands, I. W. (1951). J. Endocrin., 7, 1. 

 Bacsich, p. (1949). J. Endocrin., 6, i. 

 Bacsich, p. (1950). J. Endocrin., 7, xiv. 



