the synthetic estrogens ethinylestradiol ( 17 alpha-ethynyl-1,3,5-estratriene-3,17 beta-diol ) and mestranol [ 3-methoxy-17 alpha-ethinyl-1,3-5 ( 10 ) -estratiene-17 beta-ol ] are competitors for the estrogen receptor in the human fallopian tube .
C0015011
ethinylestradiol
C0025506
mestranol