ASSAY OF THE ANTI-OESTROGENIC EFFECTS OF PROGESTAGENS IN WOMEN

Abstract

An assay to determine the anti-estrogenic potency of progestagens in women is described. The progressive increase in endometrial glandular suppression with increasing doses of progestagens is the basis of the assay. Norethindrone (estrogen free) is 3 times as potent as chlormadinone acetate with a 95% confidence limit of 2.3 to 4.0. This is in contrast to the greater secretory potency of chlormadinone acetate. It is suggested that the anti-estrogenic action of progestagens is of some importance in the selection of compounds for contraceptives of the combined progestagen-estrogen, and of great importance for those of the continuous low dose progestagen types. This property may also be desirable in the treatment of both endometrial hyperplasia and adenocarcinoma.