Formation of pinopodes in human endometrium is associated with the concentrations of progesterone and progesterone receptors

Objective: To investigate the relation between the development of endometri al pinopodes and the serum concentration of hormones and the distribution o f estrogen receptor-alpha, estrogen receptor-beta, progesterone receptor A, and progesterone receptor B. Design: Prospective clinical study. Setting: Hospital-based unit of reproductive health and university-affiliat ed reproductive research laboratories. Patient(s): Twenty-seven healthy fertile women with normal menstrual cycles . Intervention(s): Urine and blood sampling for hormone measurement, vaginal ultrasonography, and endometrial biopsy. Main Outcome Measure(s): Appearance of the endometrium. on light microscopy , pinopode formation, serum levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH), and expression of progesterone receptors A and B and estrogen receptors alpha and beta. Result(s): Pinopode formation and regression were closely associated with i ncreases and decreases, respectively, in serum progesterone concentration. At pinopode development, levels progesterone receptors A and B in the gland ular and luminal epithelial cells decreased; this effect was mainly depende nt on the absence of progesterone receptor B. Serum estrogen levels and lev els of estrogen receptor alpha and beta did not correlate with pinopode for mation. Conclusion(s): The increase in serum progesterone level and down-regulation of progesterone receptor B are important in development of pinopodes. (Fer til Steril(R) 2001;76:782-91. (C) 2001 by American Society for Reproductive Medicine.).