Glycodelin is present in pinopodes of receptive-phase human endometrium and is associated with down-regulation of progesterone receptor B

ObjectiveTo test the hypothesis that glycodelin is localized on pinopodes and correlates with temporal immunostaining of leukemia inhibitory factor (LIF), LIF receptor (LIFR), and progesterone receptor B (PRB).DesignProspective clinical study.SettingHospital-based reproductive health unit and research laboratories.Patient(s)Twenty-five healthy fertile women with normal menstrual cycles.Intervention(s)Endometrial biopsy specimens were obtained from healthy fertile women in the luteal phase of the menstrual cycle.Main Outcome Measure(s)Immunohistochemical staining of glycodelin, ultrastructural immunostaining of glycodelin, and double staining of glycodelin and PRB.Result(s)Glycodelin is present in the glands when pinopodes appear. Glycodelin is localized on pinopodes but is also secreted from luminal epithelial cells regardless of pinopode formation. There was a negative correlation between glycodelin secretion from the glands and PRB staining. A weak correlation between the presence of LIFR (but not LIF) and glycodelin was found.Conclusion(s)Pinopode appearance, intense staining of LIFR in pinopodes and glycodelin staining in the glands are synchronized events. Down-regulation of PRB in the endometrium is concomitant with the presence of glycodelin in the endometrium, suggesting interaction.