Estrogens and epididymal function

Abstract

Estrogen is synthesized in the male reproductive system and is found in high concentrations in rete testis and seminal fluids. This luminal estrogen targets estrogen receptors (ER) along the male reproductive tract, and in particular the efferent ductules, where ERalpha is abundant. However, both ERalpha and ERbeta are found in various regions of the male reproductive tract. The transgenic ER knockout mice (alphaERKO and betaERKO) have been used to help define the role of ER in the male. In the alphaERKO animal model, the efferent ductules are dramatically altered, forming an epithelium in which fluid reabsorption is inhibited and epithelial cells have greatly reduced numbers of lysosomes and organelles associated with endocytosis. The betaERKO male reproductive tract appears normal. Because these animals are transgenic and lack ER throughout development, we developed animal models using pure antiestrogen ICI 182,780 treatments in adult males. The data show that ERalpha participates in the regulation of the apical cytoplasm of non-ciliated cells of the efferent ductules, narrow cells of initial segment epididymis and clear cells in the remaining segments of the epididymis. There appears to be no effect on vas deferens. The inhibition of ERalpha function in the male leads to decreases in sperm concentrations and eventually to infertility. The current literature leaves the mechanisms of estrogen action in the male reproductive tract unsettled and raises the question of androgen's contribution to the regulation of fluid transport, especially in the efferent ductules.

Effects of the Antiestrogen Fulvestrant (ICI 182,780) on Gene Expression of the Rat Efferent Ductules1

“…The effects of ICI 182,780 depend on the species studied, but blockade of fluid reabsorption and luminal dilation of the efferent ductules seem effects common to the species analyzed so far [15,[23][24][25]51]. Therefore, our finding that ICI 182,780 altered expression of about 60 transport-related genes was not surprising, and it is an indication that the treatment was effective.…”

“…The efferent ductules across all species express the highest concentration of estrogen receptors ESR1 and ESR2 within the male reproductive tract [2,[15][16][17][18], and the most severe histopathological changes after disruption of ESR1 occur in this organ [1,10,19,20]. The lack of ESR1 severely impairs the absorptive function of the efferent ductules, causing fluid accumulation and luminal dilation.…”

Oestrogens and spermatogenesis

“…It has been known for many years that oestrogen binds to proteins in male reproductive tissues, especially the epididymis, and now there is clear evidence that ERa (ESR1) and ERb (ESR2) are localized in specific cells of the testis, efferent ductules and epididymis, with species specificity (see reviews by Hess 2000Hess , 2003Hess , 2004Hess et al 2001Hess et al , 2002Sierens et al 2005). ERb has a rather ubiquitous expression throughout the male reproductive system, et al (1996), and Levallet et al (1998a,b) …”

Intraepithelial plasma cells in the avian copulatory organ of two tinamou species: quantitative variation during the breeding season

“…This effect has already been shown in the chicken oviduct, where oestrogens stimulate the proliferation (Khan et al 1997) and infiltration of plasma cells into the mucosa (Zheng et al 1997(Zheng et al , 2000. Oestrogens and oestrogen receptors have been found in most male reproductive organs (Hess et al , 2001, including birds (Kwon et al 1997). Therefore, it is reasonable to postulate that oestrogens would affect the male tract immune response.…”