Differential expression of estrogen receptors alpha and beta in adult rat accessory sex glands and lower urinary tract (vol 164, pg 109, 2000)

Estrogens induce pronounced structural and functional changes in male acces sory sex glands and the lower urinary tract in both sexes, but the exact me chanisms of estrogen action are not fully understood. This study was undert aken to localise the tissue cell types that express estrogen receptor in ad ult rats, and to determine the receptor subtype (ER alpha and ER beta) in o rder to identify sites that may respond directly to estrogens. In the male accessory sex glands (seminal vesicles, prostatic lobes and ampullary gland s), 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 fibromuscula r tissue surrounding the prostatic collecting ducts in the posterior periur ethral region and in ampullary gland stroma. In the epithelium of the urina ry bladder and urethra of both sexes, high level of ER beta mRNA and protei n, but no ER alpha mRNA, was detected. The connective tissue in urinary bla dder of both males and females, as well as that in prostatic urethra in mal es expressed ER alpha mRNA. The neural cells in the autonomic ganglia of th e prostatic plexus were strongly positive for ER beta mRNA, but were comple tely devoid of ER alpha. We conclude that ER beta is the predominant ER sub type 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 neura l plexus regulating the function of the lower urinary tract in males, while ER alpha. is present only in the stromal compartment of distinct sites. Th ese results indicate that in these tissues in intact adults there are multi ple targets for direct estrogen action. Furthermore, the differential or co mplementary expression of the two ER subtypes suggests that they may have s pecific functions, and may explain the complex structural and functional ch anges induced by estrogens. (C) 2000 Elsevier Science Ireland Ltd. All righ ts reserved.