Immunocytochemical Localization of Estrogen Receptors α and β in the Human Reproductive Organs

Abstract

To better define the role of estrogens in reproductive functions, we have proceeded to the immunocytochemical localization of the estrogen receptor (ER) subtypes, ER and the recently discovered ER, in human reproductive tissues. In the ovary, ER immunoreactivity was found in nuclei of granulosa cells of growing follicles at all stages from primary to mature follicles, interstitial gland, and germinal epithelium cells. Nuclear staining for ER occurred in thecal, interstitial gland, and germinal epithelium cells. In the uterus, strong ER immunoreactivity was detected in nuclei of epithelial, stromal, and muscle cells. Similar localization was obtained for ER, although the staining was much weaker. In the vagina, only ER could be detected; a nuclear reaction was observed in deep layers of the stratified epi-thelium as well as in stromal and muscle cells. In the mammary gland, both ER subtypes were observed in epithelial and stromal cells. In the testis, ER was detected in nuclei of Sertoli and Leydig cells, whereas ER immunoreactivity was only observed in Leydig cells, with no tubular labeling. In the efferent ducts, only ER could be detected, whereas neither ER nor ER could be found in the epididymis. In the prostate, ER nuclear immunolabeling was observed in both basal and secretory cells in alveoli as well as in stromal cells, whereas ER could not be detected. The present results demonstrate that there is a cell-specific localization for each of the ER subtypes in the majority of the reproductive organs studied. Moreover, they contribute to establish the exact sites of action of estrogens in male and female human reproductive systems. (