Mäkelä S, Strauss L, Kuiper G, Valve E, Salmi S, Santti R, Gustafsson J A
Department of Anatomy, University of Turku, Institute of Biomedicine, Finland.
Mol Cell Endocrinol. 2000 Jun;164(1-2):109-16. doi: 10.1016/s0303-7207(00)00233-1.
Estrogens induce pronounced structural and functional changes in male accessory sex glands and the lower urinary tract in both sexes, but the exact mechanisms of estrogen action are not fully understood. This study was undertaken to localise the tissue cell types that express estrogen receptor in adult rats, and to determine the receptor subtype (ER alpha and ER beta) in order to identify sites that may respond directly to estrogens. In the male accessory sex glands (seminal vesicles, prostatic lobes and ampullary glands), ER beta mRNA and protein were strongly expressed in the epithelium but not in the stroma, while ER alpha mRNA was present only in the fibromuscular tissue surrounding the prostatic collecting ducts in the posterior periurethral region and in ampullary gland stroma. In the epithelium of the urinary bladder and urethra of both sexes, high level of ER beta mRNA and protein, but no ER alpha mRNA, was detected. The connective tissue in urinary bladder of both males and females, as well as that in prostatic urethra in males expressed ER alpha mRNA. The neural cells in the autonomic ganglia of the prostatic plexus were strongly positive for ER beta mRNA, but were completely devoid of ER alpha. We conclude that ER beta is the predominant ER subtype in the epithelium of adult male rat accessory sex glands and the lower urinary tract of both males and females, as well as in the prostatic neural plexus regulating the function of the lower urinary tract in males, while ER alpha is present only in the stromal compartment of distinct sites. These results indicate that in these tissues in intact adults there are multiple targets for direct estrogen action. Furthermore, the differential or complementary expression of the two ER subtypes suggests that they may have specific functions, and may explain the complex structural and functional changes induced by estrogens.
雌激素会在雄性附属性腺以及两性的下泌尿道中引起显著的结构和功能变化，但其确切作用机制尚未完全明确。本研究旨在定位成年大鼠中表达雌激素受体的组织细胞类型，并确定受体亚型（雌激素受体α和雌激素受体β），以识别可能直接对雌激素产生反应的部位。在雄性附属性腺（精囊、前列腺叶和壶腹腺）中，雌激素受体β的信使核糖核酸（mRNA）和蛋白在上皮中强烈表达，而在基质中不表达，而雌激素受体α的mRNA仅存在于尿道后周区域前列腺集合管周围的纤维肌肉组织以及壶腹腺基质中。在两性的膀胱和尿道上皮中，检测到高水平的雌激素受体β的mRNA和蛋白，但未检测到雌激素受体α的mRNA。雄性和雌性膀胱中的结缔组织以及雄性前列腺尿道中的结缔组织均表达雌激素受体α的mRNA。前列腺丛自主神经节中的神经细胞雌激素受体β的mRNA呈强阳性，但完全缺乏雌激素受体α。我们得出结论，雌激素受体β是成年雄性大鼠附属性腺上皮、两性下泌尿道以及调节雄性下泌尿道功能的前列腺神经丛中的主要雌激素受体亚型，而雌激素受体α仅存在于特定部位的基质部分。这些结果表明，在完整成年动物的这些组织中存在多个雌激素直接作用的靶点。此外，两种雌激素受体亚型的差异或互补表达表明它们可能具有特定功能，这或许可以解释雌激素诱导的复杂结构和功能变化。
