GONADS AND THE PITUITARY BODY 



some cases, the single ovary of the operated animals weighed 

 twice as much as both ovaries of the normal animals which 

 also received implants. From this and other experiments it 

 may be concluded that compensatory ovarian hypertrophy 

 depends upon the secretion of gonadotropic hormone(s) by 

 the anterior pituitary. ^^ However, the gonadotropic potency 

 of the pituitary (stored gonadotropic hormone?) is not al- 

 tered by the unilateral removal of the testis or ovary (Emery, 

 Bash, and Lewis, 193 1). 



Engle (1927) found that the implantation of the pituitary 

 prevented degenerative changes and the resorption of ovarian 

 grafts placed in the abdominal muscles or the testis. In the 

 abdominal-muscle transplants (in castrated males), large 

 mature follicles could be found; in the transplants in the 

 testis, an ovariotestis was formed. The success of ovarian 

 transplants in castrated male rats, not treated otherwise, 

 probably depends upon the increased amount of gonado- 

 tropic hormone available (for the testes, if present, both util- 

 ize gonadotropic hormone and lessen its secretion by the an- 

 terior lobe). 



The gonadotropic hormone{s) and psendopregnancy. — Al- 

 though in the rat corpora lutea may persist anatomically for 

 abnormally long periods after hypophysectomy, physiolog- 

 ically active corpora lutea cannot be maintained in the ab- 

 sence of the pars glandularis. This is clearly shown in the 

 rabbit. If hypophysectomy is performed long enough after 

 copulation so that ovulation and corpus luteum formation 

 occur subsequently, the corpora lutea begin to regress after 

 about the second day.^-' Other observations on (i) pseudo- 

 pregnancy in rabbits following the injection of gonadotropic 

 hormone and (2) the amount of gonadotropic hormone in the 

 pituitary of the pseudopregnant rabbit are discussed in the 



s^ Also see chap. ii. 

 5^ See chap. ii. 



[161] 



