Prolonged gonadotropin-releasing hormone agonist therapy reduced expression of nitric oxide synthase in the endometrium of women with endometriosis and infertility

ObjectiveTo determine whether endometrial expression of endothelial nitric oxide synthase (eNOS) or inducible NOS (iNOS) protein in women with endometriosis-associated infertility is different from that in the fertile controls, whether GnRH agonist (GnRH-a) regulates the endometrial expression of NOS in women with endometriosis-associated infertility, and whether there is a correlation between serum E2 or P levels, and the endometrial expression of eNOS or iNOS.DesignProspective controlled study.SettingUniversity hospital for reproductive medicine and gynecologic endocrinology.Patient(s)Thirty patients with endometriosis-associated infertility and 19 patients with carcinoma in situ of the cervix.Intervention(s)Endometrial biopsy specimens and blood samples.Main Outcome Measure(s)Endometrial eNOS and iNOS protein relative levels and serum concentrations of E2 or P.Result(s)By Western blot analysis, iNOS was not detected, and a unique menstrual cycle-dependent expression of eNOS was observed. Eutopic endometrium in women with endometriosis-associated infertility before GnRH-a treatment showed higher levels of eNOS than that of the control group. After 3 months of GnRH-a therapy, eNOS levels in the endometrium were reduced. In addition, a significant positive correlation was found between serum E2 or P concentrations, and the endometrial expression of eNOS.Conclusion(s)The GnRH-a treatment attenuated the endometrial expression of eNOS in women with endometriosis-associated infertility. Endogenous ovarian steroids influence endometrial eNOS expression.