Immunoreactive gonadotropin-releasing hormone expression in cycling human endometrium of fertile patients

Abstract

Objective: To investigate the protein expression of GnRH in the endometrium of fertile patients throughout the menstrual cycle. Design: Prospective longitudinal study. Setting: Department of Gynecology and Obstetrics, Reproductive Immunology Laboratory, Stanford University Medical Center. Patient(s): Twenty-two fertile premenopausal women submitted to laparoscopic surgery for benign gynecologic indications. None of the 22 women had endometriosis or pelvic inflammatory disease. Intervention(s): An endometrial biopsy specimen using the Novak curette was obtained at the time of surgery. Main Outcome Measure(s): Protein expression and localization from unfractioned endometrial tissue was analyzed by immunohistochemistry. Result(s): Gonadotropin-releasing hormone is expressed at the protein level in both the endometrial stroma and epithelium throughout the entire menstrual cycle of fertile women. Immunostaining in the human epithelium reached maximal levels in the midluteal phase and was elevated in the stroma throughout the entire luteal phase. Conclusion(s): Our results demonstrate the presence of GnRH in the human endometrium at the protein level throughout the entire menstrual cycle of fertile women, with an increase in the luteal phase compared with the preovulatory endometrium.