4 Frances Carter, Marion C. Wcxjds and Miriam E. Simpson 



once daily for 4 days was found to be satisfactory; during this period a total 

 of 4 RU FSH (4 times the minimally effective dose) was injected. Many 

 healthy medium to medium large, or fully developed (large) follicles were 

 then present. The interstitial tissue was deficient, as only 4 RU FSH had 

 been given, and it would be necessary to inject 10 RU or more of this FSH 

 preparation before interstitial cells would be repaired. Ovulation did not 



Table 2. Standard Conditions for Induction of Ovulation 

 IN Hypophysectomized Rats 



follow this preparatory treatment without supplementary hormonal adminis- 

 tration. However, it could readily be induced by giving an injection of twice 

 the total preparatory dose (8 RU, likewise subcutaneously) late on the day 

 of the 4th injection (6 hr after the last preparatory dose). Observations of the 

 ovaries and oviducts to determine the incidence of ovulation were made 

 24 hr after this supplementary injection. Under these circumstances young 

 corpora lutea were present in the ovaries in 82 % of the 34 rats so treated. 

 Multiple ova were shed, and an average of 27 were present in the oviduct. 



Figure 1 shows the multiplicity of corpora lutea, interspersed with some 

 follicles which did not rupture. The large number of ova shed is indicated by 

 the clumps of granulosa cells in the loop of oviduct shown. Figure 2 shows 

 a group of ova in a distended loop of oviduct. Figure 3 shows that ova some- 

 times still lingered in the bursa at time of autopsy. 



The corpora lutea present 24 hr after the last injection were still not 

 completely formed, the predominating cell, the granulosa lutein cell, not 

 having developed much cytoplasm (Fig. 4). Rupture points were seen 

 occasionally but these close quickly in the rat (Fig. 5). 



The treatment almost always developed multiple follicles. The proportion 

 of follicles releasing ova, together with the proportion of rats in the group 

 which ovulated were used as a measure of the efficacy of treatment. With the 

 particular FSH preparation shown in Table 2 the number of ova released 



