ANTIESTROGENIC EFFECTS OF DANAZOL ON RABBIT UTERUS

To examine antiestrogenic effects of danazol through the receptor syst em and to clarify its direct effects on the endometrium in vivo, we ap plied danazol jelly directly into the rabbit uterine cavity and measur ed uterine estrogen, progesterone and androgen receptors (ER, PR and A R, respectively). Danazol significantly reduced ER, PR and AR (p < 0.0 5). Treatment with receptor-blocking agents (RU 486 and oxendolone) sh owed that the decrease in the ER level showed a closer association wit h that in PR than with AR. These results indicate that danazol directl y administered into the uterine cavity is absorbed by the endometrial tissue and exerts its antiestrogenic effects possibly through PR in th e cells.