Inhibition of Ovulation in the Human 



225 



as was also norethynodrel, which by its molecular pattern is seen to be not a 

 testosterone, but is more closely related to the classical estrogens. Details 

 of the differences in molecular configuration among these three compounds, 

 as well as the biological properties correlated with these differences, have 

 been reviewed previously (34-36). 



NORETHANDROLONE 

 I7«:-ETHYL-I9-N0RTEST0STER0NE, NILEVAR: G D. SEARLE a CO. 



NORETHYNODREL 



I7«6-ETHINYL- 5(10)- ESTRAENEOLONE 

 ENOVI0*G D SEARLE SCO 



NORETHINDRONE 



1 7o<l- ETHINYL- 1 9- NORTE STOSTE RONE 

 ^ORLUTIN PARKE, DAVIS 8 CO. 



EACH IO-m» TABLET OF ENOVID, IN ADDITION TO 9 65 mg. NORETHYNODREL, CONTAINS 

 0.15 mg. ETHYNYLESTRADIOL-3-METHYL ETHER. 



Fig. 1. Three commercially available synthetic 19-nor steroids are shown in relationship 



to the naturally occurring hormones, progesterone and testosterone. (After Crosson, J. W., 



New Synthetic Steroid Progestins. Fertil & Steril. 10, 361-373, 1959.) 



Norethynodrel (17Q:-ethinyl-5(10)-estraeneolone) is prepared and manu- 

 factured in combination with a small amount of 3-methyl-ether of ethynyl- 

 estradiol. This estrogen component was found to be present in some of the 

 original theoretically pure preparations of the 19-nor steroid. Since later 

 products lacking the estrogen were not as effective, the 3-methyl-ether of 



