Gregory C W, DePhilip R M
Department of Pediatrics, University of North Carolina at Chapel Hill School of Medicine, 27599, USA.
Biol Reprod. 1998 Feb;58(2):470-4. doi: 10.1095/biolreprod58.2.470.
Previous work established biochemical homology between proteins named SCc1 and SCc2 in FSH-treated Sertoli cell cultures and a family of 30-kDa proteins, collectively referred to as Steroidogenic Acute Regulatory protein (StAR), in hormone-treated adrenal and gonadal cells. The purpose here was to establish the presence of StAR in FSH-treated Sertoli cell cultures using a StAR-specific antiserum. Immunofluorescence microscopy and immunoblot analysis were used to detect StAR in Sertoli cell cultures and in R2C rat Leydig tumor cell cultures that served as a positive control for StAR expression. FSH dramatically enhanced the appearance of StAR in mitochondria of Sertoli cells, whereas R2C cells expressed StAR constitutively. It has been proposed that StAR participates in steroidogenesis by facilitating the conversion of cholesterol to pregnenolone by the cytochrome P450 side-chain cleavage enzyme. FSH-treated Sertoli cells were shown here to lack detectable levels of side-chain cleavage enzyme protein and RNA, while R2C cells expressed both. We conclude that the appearance of StAR in Sertoli cell mitochondria is regulated by FSH, but that its function in Sertoli cells is not associated with the conversion of cholesterol to pregnenolone.
先前的研究表明，在促卵泡激素（FSH）处理的支持细胞培养物中，名为SCc1和SCc2的蛋白质与激素处理的肾上腺和性腺细胞中的一类30 kDa蛋白质（统称为类固醇生成急性调节蛋白，即StAR）之间存在生化同源性。本研究的目的是使用StAR特异性抗血清确定FSH处理的支持细胞培养物中是否存在StAR。免疫荧光显微镜和免疫印迹分析用于检测支持细胞培养物以及用作StAR表达阳性对照的R2C大鼠睾丸间质细胞瘤细胞培养物中的StAR。FSH显著增强了支持细胞线粒体中StAR的表达，而R2C细胞则组成性表达StAR。有人提出，StAR通过促进细胞色素P450侧链裂解酶将胆固醇转化为孕烯醇酮来参与类固醇生成。本文显示，FSH处理的支持细胞缺乏可检测水平的侧链裂解酶蛋白和RNA，而R2C细胞则同时表达这两者。我们得出结论，支持细胞线粒体中StAR的出现受FSH调节，但其在支持细胞中的功能与胆固醇转化为孕烯醇酮无关。
