Effect of chronic treatment with nafarelin on estradiol receptor content within eutopic and ectopic endometrium in rabbits

Endometriosis was surgically induced in New Zealand white rabbits in the first 4 weeks. Then some animals were treated with nafarelin (Naf) at 3 daily doses (1, 3 or 10 μg·kg 1 , sc) or bilateral ovariectomy (OVx), the rest served as controls. Six weeks later, the uterine weights and estradiol receptor (ER) concentrations within eutopic endometrium in Naf treated rabbits decreased significantly. However, immunohistochemical analysis showed that Naf failed to result in obvious changes in ectopic endometrial ER content. These results imply that the suppressive effect of Naf on uteri in rabbits may be mediated by ER, while the mechanisms involved in its inhibitory effect on endometrial implants may not be related to ER.