The Role of the Pituitary Gonadotropins 5 



varied from 3 to 65, the average being high (27) so this was considered an 

 effective treatment. (At least a few of the multiple follicles stimulated always 

 enclosed ova with luteinization of their walls. Therefore a higher proportion 

 of follicles releasing their ova was evaluated as a better response, although, 

 as pointed out previously, the normality of superovulation may itself be 

 questioned.) Figure 6 shows some apparently normal follicles which did not 

 ovulate within 24 hours. It had been determined previously, however, that 

 the differences in number of ova shed between 18 and 24 hours was no greater 

 than the variation between animals, and that a longer period before autopsy 

 (28, 32, 40 hours) merely resulted in greater maturity of the corpora lutea, 

 and enclosure of the remaining ova in luteinized bodies. 



When the corpora lutea were allowed to complete their development under 

 the influence of lactogenic hormone, they could be shown to be functional. 

 The corpora lutea after administration of 2 lU daily of lactogenic hormone* 

 for 10 days were large and compact (Fig. 7) and the uteri of such animals 

 were able to produce placentomata around threads inserted through the 

 endometrium (Table 3). 



Table 3. Functional Capacity of Corpora Lutea Induced in Hypophysectomized 



Immature Rats by FSH or by FSH + HCG and Maintained for 10 days by Lactogenic 



Hormone. Placentoma Reaction 



Followed by lactogenic hormone: 2 lU daily 10 days, threads in endometrium 5th day. 



As the FSH preparation used initially in determining the standard 

 conditions for induction of ovulation contained ICSH, it was important to 

 determine the significance of each of the two gonadotropins present. Attention 

 was first directed to the adequacy of FSH unsupported to induce ovulation, 

 for which purpose FSH preparations of increasing purity and potency were 

 compared in regard to this capacity. The FSH preparations used were 



* The lactogenic hormone (prolactin) used in these studies was a gift from the Endo- 

 crinology Study Section, National Institutes of Health. 



