Role of Steroid Sulfonation as a Mechanism Controlling the Flow of Substrates through the Cascade of Steroidogenic Enzymes in the Porcine Testis

然而，在许多哺乳动物物种的雄性中，雌激素在低浓度下主要以游离形式在外周血中循环，而在公猪中，大量的游离和结合雌激素(以硫酸雌酮为主要雌激素)出现在外周血中。在猪睾丸附睾室的雌激素受体中，类固醇硫酸酯酶(STS)、雌激素磺基转移酶、芳香族酶和至少一个可能的类固醇硫酸盐转运体(SOAT)的表达密切相关，表明除了游离雌激素的从头合成外，硫化雌激素的合成、水解和运输是雌激素作用的局部控制元件。本项目的最终目的是在体内研究抑制STS对公猪性腺类固醇生成和精子发生的影响。因此，该项目第一阶段的目标是：1)弥合对STS和雌激素特异性硫酸盐转移酶SULT1E1在猪睾丸-附睾室的表达模式的了解；2)分析SOAT和其他可能的类固醇硫酸盐载体如OSCP1在猪睾丸-附睾室的细胞定位与年龄、类固醇激素生成和精子发生的关系；3)寻找一种有效的STS抑制剂，用于猪的体内应用。

Whereas in males of many mammalian species estrogens circulate in peripheral blood predominantly as free forms at low concentrations, in the boar large quantities of free and conjugated estrogens (with estrone sulfate being the predominant estrogen) occur in peripheral blood. In the porcine testicular-epididymal compartment estrogen receptors, steroid sulfatase (StS), estrogen sulfotransferase, aromatase and at least one putative steroid sulfate transporter (SOAT) are expressed in close proximity with each other, pointing to the synthesis, hydrolysis and transport of sulfated estrogens as local controlling elements of estrogenic actions in addition to de novo synthesis of free estrogens. The final goal of this project is to study in vivo the effect of StS inhibition on gonadal steroidogenesis and spermatogenesis in boars. Thus the aims of the first period of the project are 1) to close still existing gaps in the knowledge on the expression patterns of StS and the estrogen specific sulfotransferase SULT1E1 in the porcine testicular-epididymal compartment 2) to analyze the cellular localizations of SOAT and other putative steroid sulfate carriers such as OSCP1 in the testicular– epididymal compartment of the boar in relation to age, steroidogenesis and spermatogenesis and 3) to identify an effective StS inhibitor for the intended in vivo application in the boar.