Gonadotropin Releasing Hormone (GnRH) and GnRH Receptor in Normal Bladder Epithelia and Their Role in Bladder Epithelial Proliferation

Abstract

Purpose: To confirm the production of extra-hypothalamic gonadotropin releasing hormone (GnRH) and GnRH receptor in bladder mucosal epithelia, and a potential role of GnRH on the bladder, normal human bladder tissues, and primary cultured dog bladder mucosal epithelia were studied. Materials and Methods: For this study, normal human bladder tissue from 4 patients and primary cultured normal bladder mucosal epithelial cells from 2 dogs were used. For localization of extra-hypothalamic GnRH and the extra-pituitary GnRH receptor, in situ hybridization and immunohistochemical staining were done. To evaluate the roles of exogenous GnRH in bladder mucosal cells, the culture media were supplemented with charcoal stripped serum and 4 different concentrations of GnRH (0, 10 -3 , 10 -5 and 10 -7 M). The effect of exogenous GnRH was evaluated using a hemocytometer and fluorescence activated cell sorter (FACS). Results: GnRH and GnRH receptors, and their mRNA signals were localized in most of the both human bladder mucosal epithelia and dog bladder mucosal epithelia, but not in a few cells. There were no significant GnRH effects on cellular proliferation and cell cycle changes (p<0.05). Conclusions: Bladder mucosal epithelium produces GnRH and GnRH receptors, but they do not effect either the proliferation or cell cycle changes. Although the exact function of extra-hypothalamic bladder GnRH is unknown, GnRH and GnRH receptors would be assumed to have unknown autocrine or paracrine relationships with each other. (Korean J Urol 2007;48:152-157)