The Role of Steroids in the Control of Mammalian Ovulation 



45 



probably represent in part the deliberate selection of potentially active 

 substances, but it should be noted that in those groups where the proportion 

 of active compounds is lowest the potency of those deemed active is relatively 

 low. 



HO- -/ -- LXI 

 SQ-10,2,0.4 



C=CH 



CpHc 



SO-!0,l 

 0-JO,5,I,0,5jPJjO.I 

 ?H 



C3H7 



SQ-!0,2,0.4 



S0-ip,2 



Fig. 12. A^'^''-19-Norsteroids. (Dosage in milligrams. SQ = subcutaneous injections; 



O = by gavage.) 



Table 1 . The Numbers in Various Classes of Steroid Compounds 

 Tested as Ovulation Inhibitors 



One feature of our findings which requires further remark is the discrepancy 

 between activity by mouth and by injection exhibited particularly by some of 

 the more potent substances. This is illustrated in Table 2 where we present 

 the calculated minimal effective doses of five compounds which have been 

 sufficiently tested by both routes both as ovulation inhibitors and as 

 progestins. The data on oral : subcutaneous progestational potency ratios 

 are from the paper by Miyake and Pincus (4). The parallelism in relative oral 

 effectiveness is evident. The fact that XLVI is somewhat and LXII very much 

 more potent by mouth suggests that these may be transformed to more 



