Expression and Activity of Steroid Sulphatase in the Boar Testis

Abstract

Oestrogens are essential for male fertility targeting the testicular-epididymal compartment. However, the underlying mechanisms are only vaguely known and species specificities must be considered. The boar has a remarkably high testicular-oestrogen output, with the biologically inactive oestrone-sulphate being the major oestrogen occurring in the testicular vein. In the boar testis and epididymis, activity of steroid sulphatase (StS) and oestrogen sulphotransferase has been demonstrated. Thus apart from their synthesis in Leydig cells, provision of biologically active free oestrone seems also to depend on the activity and localization of these enzymes. Our aim was to establish expression patterns and activity of StS in boar testis. Testes were randomly collected from healthy boars and allotted to five age groups, five animals in each, aged 50, 100, 150, 200 and 250 days. Three extra boars aged over 250 days were castrated to obtain fresh tissue for enzyme activity tests. Immunohistochemistry detected StS only in the cytoplasm of Leydig cells and - except for day-50 group in which 65.1 +/- 4.9% (X +/- SD) of the cells were positive - expression was constant with virtually all the cells staining positive. RT-PCR and in situ hybridization confirmed expression and localization of StS mRNA. The V(max) and K(m) value (X +/- SD) for StS was 24.05 +/- 0.3 fmol/s/microg protein and 2.15 +/- 0.12 microM. These data suggest that StS within the Leydig cells of the boar is involved in modulation of testicular oestrogen bioavailability and that the site of sulpho-conjugation is not the testis but a different compartment of the testes-epididymidis complex.

SULFATION PATHWAYS: Formation and hydrolysis of sulfonated estrogens in the porcine testis and epididymis

“…Firstly, in the systemic circulation of adult boars, unconjugated estradiol-17β and estrone circulate at significant concentrations (Wagner et al 2006, Hoffmann et al 2010, Schuler et al 2014, questioning the need for a sulfate pathway in estrogenresponsive tissues. Moreover, in the porcine testis STS is highly and specifically expressed in Leydig cells (Mutembei et al 2009), which -as mentioned earlier -obviously possess a high capacity to produce unconjugated estrogens (UE) de novo. Accordingly, due to these seemingly inconsistent observations, so far no plausible concept has been put forward concerning the biological role of SE produced in the porcine testicular-epididymal compartment.…”

“…Real-time RT-qPCR was performed in a CFX96 Real-time Thermal Cycler by means of the SYBR green method using SYBR Green I Master Mix (both from Bio-Rad). The primer pair specific for STS was adopted from a previous publication (Mutembei et al 2009; for information on primer pairs see Table 1). Primer pairs for SULT1E1 and SULT1A1 were designed and purchased from Eurogentec (Cologne, Germany).…”

Free and sulfated steroids secretion in postpubertal boars (Sus scrofa domestica)

“…The key elements of such a pathway have already been described, such as the production of high amounts of sulfated estrogens (Claus & Hoffmann 1980, Schwarzenberger et al 1993, Zamaratskaia et al 2004, Hoffmann et al 2010, considerable expression and activity of steroid sulfatase in porcine Leydig cells and Table 2 Results from pairwise correlation analyses (cross-correlation between time series) for a linear correlation between the logarithms of the steroid concentrations assessed in seven hCGstimulated boars (SB1-7). Free and sulfated steroids in boars epididymis, and substantial estrogen sulfotransferase activity in the epididymis (Mutembei et al 2009, Hoffmann et al 2010, Zdunczyk et al 2012. Moreover, various cell types of the porcine testis and epididymis exhibit a high expression of estrogen receptors (Mutembei et al 2005, Pearl et al 2007.…”

“…This sulfatase pathway has been identified as the major route of local estrogen production in human hormone-dependent breast cancer tissues (Santner et al 1984, Reed et al 2005. Interestingly, in the porcine testicular-epididymal compartment not only the production of high amounts of sulfated steroids was observed but also a considerable expression of steroid sulfatase (Mutembei et al 2009, Hoffmann et al 2010, Zdunczyk et al 2012.…”

Testicular Steroid Hormone Secretion in the Boar and Expression of Testicular and Epididymal Steroid Sulphatase and Estrogen Sulphotransferase Activity

“…Results of the immunolocalization of StS in testes samples together with data on the enzyme kinetics have already been published ( Mutembei et al, 2009 ), and hence will only be discussed in light of the observations presented here.…”