THE PITUITARY BODY 



both the germinal epitheHum and the interstitial tissue were 

 stimulated by the gonadotropic hormones of the castrated 

 rat's pituitary. The effects were much less evident if the 

 hypophysectomized male rat was joined to a normal rat or a 

 rat with experimental cryptorchidism (Cutuly and Cutuly, 

 1937; Cutuly, McCullagh, and Cutuly, 1937). From a study 

 of the changes in the accessory organs and testes which tend- 

 ed to be parallel, the authors suggest that the testicle requires 

 only one gonadotropic hormone, whereas the ovary may re- 

 quire two. M0ller-Christensen (1935) has published a long 

 report of his experiments with rats in parabiosis. He has ad- 

 vanced the view that in the experiment 9 ? , the pituitary 

 of the normal rat inhibits the activity of its own ovaries. He 

 cites the experiment 9 h § : cystic ovaries without corpora 

 iutea are found in the hypophysectomized rat; atrophy of 

 secondary organs in the spayed female is moderate and not 

 advanced. ^^ In the experiment 9 9 , of course, the ovaries of 

 the normal female may become cystic; this change can be 

 observed more certainly in the experiment 9 sT- The pitui- 

 tary of the normal female of the partners 9 § or 9 sf under- 

 goes hypertrophy and contains no gonadotropic hormone 

 (M^ller-Christensen). x^nother type of parabiosis investi- 

 gated by the author was that symbolized by 9 h 9 • Normal 

 oestrous cycles and normal sexual organs were observed in 

 the normal rat; the gonads and accessory organs of the hy- 

 pophysectomized rat underwent atrophy. The interpretation 

 of all these results, especially in terms of an inhibiting effect 

 of the pituitary on ovarian function, is a suggestion requiring 

 more supporting data. The contrary effect — increased re- 

 lease (and diminished utilization) of gonadotropic hormone by 

 the pituitary after gonadectomy — still appears to be the best 

 interpretation of most experiments with parabiotic rats. 

 3. The effects of the internal secretions of the gonads on pitui- 



^* Oestrus in the spayed partner is observed more frequently in the experiment 

 9h'?i than in the experiment 9 ?! (M0ller-Christensen, 1933). 



[80] 



