14 



Frances Carter, Marion C. Woods and Miriam E. Simpson 



In order to determine whether these results were pecuHar to rat pituitary 

 gonadotropins, an clTort was made to reconstitute the proportion in rat 

 pituitary ethanol extracts by use of sheep pituitary gonadotropins. Purified 

 sheep FSH and ICSH preparations were therefore combined in the proportion 

 1 : 4, and were given at unitages corresponding to those of the rat pituitary 

 preparations (Table 15). Sheep gonadotropins in doses of 4 RU FSH+ 16 RU 



Table 15. Induction of Ovulation by a 40% Ethanol Extract of Rat PrrurrARY, or 

 BY Sheep FSH and ICSH combined in the Same Proportion 



ICSH caused luteinization of follicles with enclosure of ova, even before 

 supplementation. Half these unitages, 2 RU FSH + 8 RU ICSH, caused 

 follicular development, but even without supplementation occasionally 

 caused ovulation, as had the rat pituitary extract at this level; optimal 

 conditions for ovulation were attained only when the usual supplement was 

 administered. Mixtures of 1 RU FSH + 4 RU ICSH did not give adequate 

 follicular growth in the first phase of treatment and the supplementary dose 

 was therefore ineffective, so that such mixtures were slightly inferior to the 

 rat pituitary preparations. 



Several purified FSH preparations were combined with ICSH in this ratio 

 (1 : 4) and when given at the optimal dose level, 2 RU FSH and 8 RU ICSH, 

 were equally effective in promoting follicular development. When this was 



