Androgen, estrogen and progesterone receptor expression in the human uterus during the menstrual cycle

Cyclic changes in steroid receptor expression in endometrial cells are cons idered a reflection of its differential functions. Besides estrogen and pro gestogens, androgens have also been suggested to affect the biological func tion of the female reproductive tract. We investigated the distribution and intensity of immuno-cytochemical estrogen receptor (ER), progesterone rece ptor (PR) and androgen receptor (AR) staining in the various cell types of human endometrium and myometrium during the different menstrual cycle phase s in 30 paraffin-embedded sections. AR expression in endometrial stromal cells decreased gradually from early p roliferative till mid secretory phase. In the late secretory phase, AR expr ession in all cell types distinguished. Staining of epithelial cells was mo derate. The disappearance of AR expression before cyclic separation of endometrial tissue may be causally related or just an epiphenomenon. Due to local compe tition for 5 alpha -reduction of testosterone and the excess of progesteron e in the secretory phase, the level of dihydrotestosterone (DHT) will be di minished. Hypothetically, if AR synthesis in endometrium would be DHT-depen dent, it would explain the lack of AR expression in the late secretory phas e. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.