Estrogen Receptors and Estrogen-Regulated Genes in the Male Reproductive Tract

116 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2002.Estrogen receptor-alpha (ERalpha) is essential for male fertility. The bisexual role and importance of estrogen in reproduction was established by the previous studies. However, there is considerable variation, both within and between species, in reports of nuclear steroid receptor localizations in the male reproductive tract. Therefore, in the first part of this thesis, the cellular expression of androgen (AR) and estrogen receptors, ERalpha and ERbeta, were investigated by immunohistochemistry in the adult male mouse reproductive tract. It was demonstrated that ERalpha is expressed in a region and cell specific manner along with AR and ERbeta in mouse reproductive tract, and this expression pattern of ERalpha in mice differs considerably from the rat. It has been shown that estrogen regulates the fluid reabsorption for concentrating sperm in efferent ductules. In second study, the potential estrogen-regulated genes involved in fluid reabsorption were examined in alphaERKO and ICI-treated mice. We demonstrated that estrogen regulates one of the most important epithelial ion transporters, Na+/H+ exchanger-3 (NHE3), and then influences the passive transepithelial water movement in efferent ductules. In addition to its regulation of Na + transport, estrogen also maintains epithelial morphological differentiation in efferent ductules of the male. Moreover, these data raise the possibility of targeting ERalpha in developing a contraceptive for the male. The third part of the thesis is to determine the downstream gene mediating estrogen action on epithelial terminal differentiation, and a cell polarity gene, hensin, was studied in the male reproductive tract. It was shown that hensin is expressed extensively in the male reproductive tract. The cellular and subcellular localization of hensin indicates its two potential functions in male tissues: involvement of cell differentiation and immune defense. Orchidectomy and hormone supplement studies suggested that the expression of hensin is not regulated by either estrogen, or androgen or any other testicular factors in the male tract. Morphometry data suggested that androgen alone is able to maintain the epithelial cell morphology and AR expression in adult efferent ductules. Indirect evidence from this study further confirms the established role of ERalpha in cell morphological differentiation.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD