Antifibromatogenic Activity of 19-Nor-a-ethinyltestosterone in the Guinea Pig.

Abstract
The antifibromatogenic potency (prevention of estrogen-induced abdominal fibroids) of 19-nor-[alpha]-ethinyltestos- terone is about 4 times that of ethinyltestosterone. The 19-nor compound is also greatly superior in antihysterotropic potency, i.e. in preventing uterine increase due to estrogen.