GONADS AND THE PITUITARY BODY 



was more potent than the normal. The potency of the female 

 rabbit's pituitary appeared not to be altered as a result of 

 ovariectomy. However, Hill (1934), who also performed his 

 assays by producing ovulation in rabbits, concluded that 

 gonadectomy caused a reduction in the gonadotropic potency 

 not only of the pituitary of the female and male rabbit, but 

 also of the pituitary of the male cat. Still other results were 

 obtained by Smith, Severinghaus, and Leonard (1933), who 

 investigated the gonadotropic potency of the pituitary of 

 normal and gonadectomized rabbits. By the ovulation test, 

 the pituitary of the spayed female was more potent than the 

 normal female pituitary.-'^ In terms of its effects on the ovary 

 of the immature mouse, the pituitary of castrated or spayed 

 rabbits was more potent than the pituitary of normal males 

 or females. The change in potency was more pronounced in ' 

 the female rabbits. 



It is well known that spayed women excrete considerable 

 amounts of gonadotropic hormone (usually described as folli- 

 cle-stimulating)." Probably this is a secretion of the an- 

 terior lobe (see chap. v). 



Therefore, in the rat, guinea pig, rabbit, and man, there is 

 evidence that gonadectomy is followed by an increased secre- 

 tion (and storage?) of gonadotropic hormone(s) by the an- 

 terior lobe of the pituitary.-'^ This fact suggests that the in- 

 ternal secretions of the gonads inhibit the secretion of gon- 

 adotropic hormone by the anterior lobe. Also in favor of this 

 view are numerous experiments in which hormones of the 

 ovaries or testes (either extracts of the gonads or hormones 

 obtained elsewhere [e.g., urine] but having effects on the 

 secondary organs like the true internal secretions) have been 

 used. It will be pointed out later that all these data may be 



^' Similar experiments were not performed with male rabbits. 



37 The pars glandularis of the male horse appears to produce a stimulation of 

 follicle growth, particularly if it is obtained from a castrated male (Hellbaum, 1933). 



3* Different results were obtained by Hill (1934). See the preceding discussion. 



[15^ 



