172 INTERNAL SECRETIONS OF THE OVARY 



causes the corpora lutea of the immediate post-partum ovulation 

 to persist means presumably that lactation influences the 

 anterior pituitary body, causing it to exert the luteinizing 

 stimulus. Then again, premature weaning apparently causes 

 the anterior pituitary body to exert its stimulus to follicular 

 maturation. 



Influence of events in the ovary on the anterior pitnitary. It is 

 well known that the ovarian cycle can be expedited by various 

 means such as puncturing the maturing follicles (478) or 

 removing young corpora lutea (265). This might theoretically 

 be explained in either of two ways: 



[a) That the alteration in the ovary has expedited a cycle in 



the anterior pituitary. 

 [h) That anterior pituitary substance is made available for 



corpora lutea by the destruction of follicles, and vice 



versa. 



The latter view would presuppose the presence of only one 

 anterior pituitary substance, and also the absence of endocrine 

 cycle in the anterior pituitary. 



The occurrence of the cycle in X-ray sterilized animals 

 shows that it is not brought about by follicles and corpora lutea 

 alternately utilizing a single anterior pituitary substance. 

 Hence, hypothesis [h) is invalidated and hypothesis (a) must be 

 accepted. Thus, cyclic endocrine activity exists in the anterior 

 pituitary, even if only one substance is produced. It is 

 evident, therefore, that events in the ovary may, under certain 

 conditions, influence the cycle in the anterior pituitary. 



