Localization of oestrogen receptor alpha, oestrogen receptor beta and androgen receptors in the rat reproductive organs

There is now evidence that oestrogens and androgens can influence male and female reproductive systems. In order to accurately identify the sites of a ction of oestrogens and androgens, we have proceeded to the histological lo calization of the two oestrogen receptor (ER) subtypes, ER alpha and ER bet a, and the androgen receptor (AR) in the reproductive tissues of adult rats of both sexes. AR was detected by immunocytochemistry, while ER alpha and ER beta were localized by both immunocytochemistry and in situ hybridizatio n. In the pituitary gland of animals of both sexes, ER alpha was found in t he majority of nuclei of secretory cells in the anterior pituitary. The int ermediate and posterior lobes did not show any staining. ER beta was not fo und to be expressed in any of the pituitary lobes. Using AR antibodies, nuc lear staining was detected in about 50% of secretory cells of the anterior lobe, the intermediate and posterior lobes being completely unstained. In t he testis, ER alpha was localized in nuclei of Leydig cells as well as in r ound spermatocytes and spermatids, while ER beta could only be detected in Sertoli cell nuclei. AR immunoreactivity was found in nuclei of Sertoli, pe ritubular myoid and Leydig cells. In the prostate, ER beta was observed in epithelial cells of tubulo-alveoli, while the stroma was unlabelled. ER alp ha was not found to be expressed in any prostate cells. In the prostate, AR was detected in nuclei of epithelial, stromal and endothelial cells. In se minal vesicles, staining of ER alpha was found in nuclei of epithelial and stromal cells. Similar findings were observed using AR antibodies. While ER beta mRNA could not be detected by in situ hybridization, weak staining fo r ER beta was localized in epithelial cells of seminal vesicles. In the ova ry, both ER alpha and ERP were found to be expressed. ER beta mRNA was foun d in granulosa cells of growing follicles, while ER alpha was present in th eca cells, interstitial gland cells and germinal epithelium. AR immunoreact ivity was detected in granulosa cell nuclei in growing follicles and also i n scattered interstitial cells. In the oviduct and uterus, ER alpha was obs erved in nuclei of epithelial cells as well as of stromal and muscle cells. Similarly, AR immunoreactivity was present in nuclei of epithelial cells, stromal and muscle cells in both the oviduct and uterus. ER beta was not de tected in the oviduct and uterus. The present findings indicate a cell-spec ific localization of ER alpha, ER beta and AR in reproductive tissues in ra ts of both sexes. By establishing the precise sites of action of oestrogens and androgens they contribute to a better understanding of the respective role of these steroids in reproduction function.