126 Discussion 



Gillman : Is there any sex difference in amyloidosis ? 



Miihlbock: We found no such difference, except in organs which 

 themselves show sex differences as, for instance, the adrenal cortex. 

 However, because of our work on mammary cancer we do most work 

 with female mice and we have much more experience with female 

 animals than with males. 



Gillman: I asked that question because my brother, Prof. Joseph 

 Gillman, and Dr. Christine Gilbert have recently described quite a high 

 incidence of spontaneous amyloidosis in the female baboon. This they 

 consider in some way to be related to the cyclical absorption of the sex 

 skin material (Gillman, J., and Gilbert, C. (1955). Acta med. scand., 152, 

 suppl. 306, 155). One wonders whether the cyclical alterations in the 

 connective tissues associated with ovarian activity may not contribute 

 towards the amyloidosis in Dr. Miihlbock's animals. 



Parkes: I was fascinated by many of the experiments which Dr. 

 Miihlbock described, and I would like to congratulate him. 



The young mice which received the old ovaries as a graft gradually went 

 off cycle ; what was the histological condition of the graft by that time ? 



Miihlbock: We don't find much of them; there is some cell growth 

 remaining. 



Parkes: What was the histological condition of the old ovaries when 

 they went in as a graft ? Was the failure of the ovary to keep up its 

 endocrinological secretion after grafting due to exhaustion of the supply 

 of eggs or to something else ? 



Miihlbock: I think it was due to exhaustion. 



Parkes: The grafting would have destroyed a lot of the remaining eggs 

 and a few cycles might exhaust the ovary altogether. 



Miihlbock: I think that is exactly what happens. 



Franklin: Dr. Miihlbock, what was the safe distance apart for your 

 animals not to get pseudopregnancy as a result of smelling one another? 



Miihlbock: If you just take a cage that has been soiled by the animals 

 and put an animal in there it will become pseudopregnant. 



Best: That will involve an estimation of the acuity of the sense of 

 smell? 



Franklin: Yes, it does. 



Krohn: I am not at all certain that you are right when you suggest 

 that the ovarian function stops when there are no more ova. It is my 

 impression that the ovaries of old animals which have gone on cycling 

 for some considerable time after they have become infertile still look 

 quite healthy histologically. There is plenty of granulosa-like tissue but 

 there are no ova or oocytes in the ovaries themselves. I think the two 

 functions do not stop at the same time; they can be separated in time 

 and probably by a period of six or seven months or so. 



Miihlbock: However, we found that oestrus cycles may continue while 

 fertility has stopped. This cessation of fertility appears to be due to 

 ovulatory failure, and in the ovaries no normal follicles are found. 



Krohn: Yes, but I believe those animals have not or may not have 

 any ova at all in the ovary. It is not that they are ovulating inadequate 

 ova, but that if you look at the ovaries of old animals which are still 



