The Role of the Pituitary Gonadotropins 3 



lower AS concentrations (Table 1). Such preparations are commonly called 

 "FSH", because instigation of follicular growth is their predominant 

 biological characteristic. No corpora lutea are produced until many multiples 



Table 1. Ammonium Sulfate Method for Fractionation of Gonadotropins from 

 40 % Ethanol Extract of Dried Whole Sheep Pituitaries 



830 g dried whole sheep pituitaries 



40% Ethanol pdr. 43 g 

 extr. 1.25LH20pH4RT 



insol. 19.4g soluble 15 g (organic) 



Add solid ammonium sulfate (AS) 



ppt. 0.2 SAS: reppt. 



0.5 SAS ppt. 



0.8 SAS ppt. 



0.2 SAS 



I 



0.5 SAS ppt. / 

 \ / 



re-extr. 50 cm* H2O pH 4 



re-extr. 400 cm^ H2O pH 4, adj. pH 5 



0.2 SAS ppt. 



0.5 SAS ppt. 



0.2 SAS ppt. 0.5 SAS ppt. 



0.8 SAS ppt. 



wash 0.5 SAS: dial, ppt. dry 1.7 g 

 re-extr. 100 cm^ HoO pH 4 



0.1 SAS ppt. 



3rd 0.5 SAS ppt. 

 SVI 11 B 0.75 g 

 ICSH MED 15 ^g 



dial, dry 2.7 g ext. 0.4 SAS pH 4 



0.4 SAS insol. 



sol.; to 0.8 SAS 



3rd 0.8 SAS ppt. 

 SVI 3 B 0.8 g 

 FSH MED 25 /xg 



of the minimal effective dose are given. Since microscopic evidence of repair 

 of the interstitial tissue was found on injection of this preparation at 10-fold 

 the dose giving follicular development it was characterized as containing 

 10% ICSH. 



In experimental induction of ovulation in the hypophysectomized rat, both 

 dosage and timing of administration of the hormones are of utmost im- 

 portance. Rats hypophysectomized at 26 to 29 days of age were used in 

 experimentation 7 days after the operation, which allowed time to determine 

 completeness of hypophysectomy on a body weight basis, to insure ehmina- 

 tion of circulating endogenous hormones, and to establish a reasonably 

 uniform degree of atrophy of the reproductive tract. Table 2 shows the 

 standard conditions adopted for induction of ovulation. Adequate follicular 

 development had to be induced, and for this, subcutaneous injection of FSH 



