Department of Gynecology and Obstetrics, Second Xiangya Hospital, Central South University, Changsha 410011, China

Objective To examine expression of GnRHⅡ protein in patients with and withoutendometriosis and to determine its relation to the menstrual cycle.MethodsThe expression of GnRHⅡ protein was detected in the normal, ectopic, eutopic endometrial tissues in women with and withoutendometriosis via immunohistochemistry SP method. ResultsGnRHⅡ was located in the cytoplasm of endometrial stromal cells and gland cells in all specimens. The expression of GnRHⅡ was lower in the ectopic endometrium than that in eutopic endometrium of patients with endometriosis （P＜0.05）, and it was lower in the eutopic and ectopic endometrium of patients with endometriosis than that in the endometrium of women without endometriosis (P＜0.05).The expression of GnRHⅡ was obviously higher in the early and middle secretory phase than that in the hyperplasia phase in normal endometrium (P＜0.05). However, there was no significant difference between the eutopic and ectopic endometrium in patients with endometriosis in the menstrual cycle (P＞0.05).Conclusion The expression of GnRHⅡ in the ectopic and eutopic endometrium may play a crucial role in the pathogenesis of endometriosis and human menstrual physiology.