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，雌激素主要以低浓度的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（硫酸雌酮是主要的雌激素）出现在外周血中。在猪睾丸-附睾区室雌激素受体，类固醇硫酸酯酶（StS），雌激素磺基转移酶，芳香化酶和至少一个假定的类固醇硫酸盐转运蛋白（SOAT）的表达彼此非常接近，指向的合成，水解和运输的硫酸化雌激素作为局部控制元素的雌激素作用，除了从头合成的游离雌激素。本项目的最终目的是在体内研究StS抑制对公猪性腺类固醇生成和精子发生的影响。因此，该项目的第一阶段的目的是1）填补关于猪睾丸-附睾隔室中StS和雌激素特异性磺基转移酶SULT 1 E1的表达模式的知识中仍然存在的空白，2）分析SOAT和其他推定的类固醇硫酸盐载体如OSCP 1在公猪睾丸-附睾隔室中与年龄相关的细胞定位，类固醇生成和精子生成和3）鉴定用于在公猪中预期的体内应用的有效StS抑制剂。

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.