%0 Journal Article
%T Effects of 3-beta-diol, an androgen metabolite with intrinsic estrogen-like effects, in modulating the aquaporin-9 expression in the rat efferent ductules
%A Patr¨ªcia Picciarelli-Lima
%A Andr¨¦ G Oliveira
%A Adelina M Reis
%A Evanguedes Kalapothakis
%A Germ¨¢n AB Mahecha
%A Rex A Hess
%A Cleida A Oliveira
%J Reproductive Biology and Endocrinology
%D 2006
%I BioMed Central
%R 10.1186/1477-7827-4-51
%X To test this hypothesis, adult male rats were submitted to surgical castration followed by estradiol, DHT or 3-beta-diol replacement. Changes in AQP9 expression in the efferent ductules were investigated by using immunohistochemistry and Western blotting assay.Data show that, after castration, AQP9 expression was significantly reduced in the efferent ductules. 3-beta-diol injections restored AQP9 expression, similar to DHT and estradiol. The results were confirmed by Western blotting assay.This is the first evidence that 3-beta-diol has biological activity in the male reproductive tract and that this androgen metabolite has estrogen-like activity in the efferent ductules, whose major function is the reabsorption of luminal fluid.Fluid homeostasis is critical for normal function of the male reproductive tract and aquaporins (AQP) play an important role in maintenance of this water and ion balance [1-3]. Some of these integral membrane proteins allow transcellular movement of water, a function associated with their name, but other AQPs permit the movement of small solutes [4]. At least 13 mammalian isoforms (AQP0-AQP12) have been identified, particularly in fluid-transporting tissues, but also in cells not recognized for this activity [5-7]. Several AQPs are expressed in the male genital tract, with specific isoforms identified in testes, efferent ductules, the epididymis and vas deferens [8-12].The efferent ductules are a major site for fluid homeostasis, as they reabsorb more than 95% of the luminal fluid released from the seminiferous epithelium [13]. These small coiled ductules transport sperm from the rete testis and play a major role in concentrating sperm prior to their maturation in the epididymis [14,15]. The male excurrent ductal epithelia express at least four AQPs, with 1, 9 and 10 found in the efferent ductules and 1,3, and 9 reported in the epididymis [9-11,16-18]. Although AQP1 and 9 are common to both the efferent ductules and epididymis, regulation of
%U http://www.rbej.com/content/4/1/51