The Role of Steroids in the Control of Mammalian Ovulation 



39 



Seven compounds classifiable as androgens and their derivatives (Fig. 3) 

 are clearly of low or marginal potency. 



Among a large number of progesterone derivatives and analogs tested, we 

 list in Fig. 4 two epoxides (XVII and XVIII) which gave marginal indications 

 of activity, two 16-substituted compounds of which one (XX) is clearly of 



CH,COQ 



CHXOO 



0'/ ^^ ^^ SK 



SQHq,2,0.4,0.08 



,-CH, 



Fig. 3. Androgens and derivatives. (Dosage in milligrams. SQ = subcutaneous injection; 



O = by gavage.) 



low potency and the other (XIX) is inconsistently active by injection and 

 of low potency by mouth, and Il-keto-A«-progesterone (XXI) which is of 

 moderate potency by injection. In Fig. 5, among the 21 -substituted pro- 

 gesterone derivatives only 21-fluoroprogesterone (XXVI) shows consistent 

 activity to a dosage as low as 0.4 mg per rabbit. Among a group classified as 

 miscellaneous progesterone derivatives (Fig. 6) only one, XXIX, is con- 

 sistently inhibitory by the subcutaneous route. It appears to be inactive on 

 oral administration. 



The reported high progestational activity of certain derivatives of 17- 

 hydroxyprogesterone (4, 5) led us to test a number of them (Figs. 7 and 8). 



4 



