Arylhydrocarbon receptor expression in the human endometrium

Abstract

Objective: To determine the expression and localization of the arylhydrocarbon (dioxin) receptor in human endometrium throughout the normal menstrual cycle. Design: Retrospective immunohistochemical and in situ hybridization study. Setting: Academic research unit. Patient(s): Premenopausal women (n = 86), aged 25 to 45 years, with histologically normal endometrium undergoing curettage or hysterectomy. Intervention(s): Endometrial samples were collected from days 3 to 26 of the cycle by superficial scrapings of the uterine cavity or by hysterectomy. Main Outcome Measure(s): Expression of arylhydrocarbon receptor mRNA and protein. Result(s): Arylhydrocarbon receptor was expressed in 43% of the endometria studied and was correlated with the day of the cycle. The maximum of immunopositive endometria was found around the time of ovulation. Immunostaining decreased with increasing age of the patients. The receptor protein was localized exclusively in the apical part of the cytoplasm in the epithelial cells of the endometrial glands. In women positive for arylhydrocarbon receptor, arylhydrocarbon receptor mRNA was expressed in the cytoplasm of endometrial epithelial cells. Conclusion(s): Our results describe the expression of the arylhydrocarbon receptor in human endometrium and indicate a possible involvement of this transcription factor in endometrial function in women during the reproductive phase.