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

<bold>Objective: </bold>To 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). <bold>Design: </bold>Prospective clinical study. <bold>Setting: </bold>Hospital-based reproductive health unit and research laboratories. <bold>Patient(s): </bold>Twenty-five healthy fertile women with normal menstrual cycles. <bold>Intervention(s): </bold>Endometrial biopsy specimens were obtained from healthy fertile women in the luteal phase of the menstrual cycle. <bold>Main Outcome Measure(s): </bold>Immunohistochemical staining of glycodelin, ultrastructural immunostaining of glycodelin, and double staining of glycodelin and PRB. <bold>Result(s): </bold>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. <bold>Conclusion(s): </bold>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. [ABSTRACT FROM AUTHOR]