Further investigation of the antiovulatory effects of the antiprogestational steroid RMI 12,936 in the rat

Investigation of the influence of progesterone on mouse embryo transport by using antiprogestational steroids

“…Since no entirely specific agents of this type are available two steroids with different mechanisms of antiprogestational activity and different spectra of other biological activities were used. RMI 12,936 (17ß-hydroxy-7a methyl androst-5-en-3-one) is an antiprogestational steroid with weak oestrogenic, antioestrogenic and androgenic activities; it inhibits progesterone secretion and may be metabolized to a further compound which antagonizes the effects of progesterone (Kendle, 1975(Kendle, , 1976(Kendle, , 1978Grunwell, Benson, Johnston & Petrow, 1976;Geddes, Kendle, Shanks & Steven, 1979). R2323 (13-ethyl-17-hydroxy-18,19-dinor-17a-pregna-4,9,ll-trien-20-yn-3-one) has weak oestrogenic, weak andro¬ genic and antioestrogenic activities and is a competitive antagonist of progesterone (Sakiz & Azadian-Boulanger, 1971;Sakiz, Azadian-Boulanger & Raynaud, 1974;Raynaud et al, 1975).…”