five other 19-nortestosterones ( 19-nortestosterone , 17 beta-hydroxyestra-4 , 9 ( 10 ) -dien-3-one , norethindrone , norethindrone acetate , and r 2323 ) proved to be mixed agonists/antagonists .
C0028356
norethindrone
C0068980
norethindrone acetate