OVARY AND THE ANTERIOR PITUITARY BODY 153 



{b) LUTEINIZATIOX OF THE CxRAAFIAX FOLLICLE 



Evans (182) found that large amounts of a saline extract of 

 ox anterior pituitary, when injected daily into the normal rat, 

 resulted in the disappearance of the oestrous cycle during the 

 whole time that injections were carried out. This suppression 

 of oestrus was found to be associated with remarkable changes 

 in the ovary. All Graafian follicles which had reached the size 

 at which the antrum appears had undergone luteinization, 

 namely, had formed corpora lutea atretica without the inter- 

 mediate act of ovulation. As the result of this, the ovaries of the 

 injected animals came to consist mainly of a large mass of corpora 

 latea in which were embedded the remains of the ova. At the 

 cessation of injection the oestrous cycle returned after varying 

 periods of time. It has since been shown (502, 610) that the 

 luteal tissue produced as a result of this treatment is remarkably 

 healthy and will perform all the functions normally associated 

 with the corpus luteum. 



Preparation of extract. Evans' early extracts were merely 

 made with saline, but his technique was subsequently im- 

 proved and elaborated as follows (610): Anterior lobes of ox 

 pituitaries were carefully dissected out, washed, and partially 

 sterilized in 70 '\j alcohol. The tissue was then ground in a 

 mortar and extracted over-night on ice with O'lA^ sodium 

 hydroxide. After extraction, the macerated preparation was 

 neutralized to phenol red with 0-2 A^ acetic acid. After centri- 

 fuging, the supernatant fluid was used for injection in amounts 

 of about I c.c. per day, equivalent to about i gm. of original 

 tissue. The extracts were injected intraperitoneally by Evans 

 and his collaborators, and their results have been criticized on the 

 grounds that the effects ma}^ have been due to the introduction 

 of irritating material into the peritoneal cavity. It has been 

 shown, however, that the same result can be produced by 

 subcutaneous injection (500), and adequate controls with other 

 tissues have shown quite definitely that the luteinizing effect is 

 due to some principle of the anterior lobe of the pituitary. 



Histological effects. The first histological effect on the ovary 

 of the injection of such extracts is swelling of the follicular 

 epithelium, with corresponding crushing in of the antrum 



