Terpstra P, Rommerts F F, van der Molen H J
J Steroid Biochem. 1985 Jun;22(6):773-80. doi: 10.1016/0022-4731(85)90285-7.
The possible role of LH or dcAMP induced changes in polyphosphorylated phospholipid metabolism in the regulation of cholesterol side-chain cleavage activity has been studied in tumour Leydig cells. Mitochondria isolated from LH-stimulated Leydig cells were 400% more active in pregnenolone production than mitochondria from control cells. Steroid production in isolated mitochondria from control cells could be stimulated only 25% by cytosol fractions from stimulated cells and 100 microM phosphatidyl inositol-4'-phosphate (PtdIns4P). Other polyphosphorylated phospholipids were either inactive or showed aspecific effects. During a preincubation period tumour cells were labelled with [32P]phosphate and steady-state labelling was obtained for the pholyphosphorylated phospholipids after 40-60 min. [32P]Phosphate incorporation in Ptd Ins4P, phosphatidyl inositol (PtdIns), phosphatidyl choline (PtChl), phosphatidyl ethanolamine (PtdEtn) and cardiolipin (CL) was not affected by treatment of the Leydig cells with LH which stimulated (6-fold), or with cycloheximide which suppressed (4-fold) steroid production. A 25% increase of phosphate incorporation by LH was observed only in phosphatidyl inositol-4',5'-biphosphate (PtdIns4,5P2). 32P Incorporation in PtdIns4,5P2, PtdIns,PtdEtn and CL was stimulated by quinacrine 50 microM. Under these conditions the LH-stimulated pregnenolone production but not the 25-hydroxycholesterol dependent pregnenolone production, was completely inhibited. The results obtained with isolated mitochondria and intact cells indicate that increased levels of polyphosphorylated phospholipids are not consistently correlated with increased mitochondrial pregnenolone production. This argues against an important role of polyphosphorylated phospholipids in the hormonal regulation of cholesterol side-chain cleavage activity in tumour Leydig cells.
在肿瘤性睾丸间质细胞中，研究了促黄体生成素（LH）或双丁酰环磷腺苷（dcAMP）诱导的多磷酸化磷脂代谢变化在胆固醇侧链裂解活性调节中的可能作用。从LH刺激的睾丸间质细胞中分离出的线粒体，其孕烯醇酮生成活性比对照细胞的线粒体高400%。来自对照细胞的分离线粒体中的类固醇生成，仅能被刺激细胞的胞质溶胶组分和100微摩尔磷脂酰肌醇-4'-磷酸（PtdIns4P）刺激25%。其他多磷酸化磷脂要么无活性，要么显示非特异性作用。在预温育期，用[32P]磷酸盐标记肿瘤细胞，40 - 60分钟后获得多磷酸化磷脂的稳态标记。用刺激类固醇生成（6倍）的LH或抑制类固醇生成（4倍）的环己酰亚胺处理睾丸间质细胞，对Ptd Ins4P、磷脂酰肌醇（PtdIns）、磷脂酰胆碱（PtChl）、磷脂酰乙醇胺（PtdEtn）和心磷脂（CL）中[32P]磷酸盐的掺入没有影响。仅在磷脂酰肌醇-4',5'-二磷酸（PtdIns4,5P2）中观察到LH使磷酸盐掺入增加25%。50微摩尔的奎纳克林刺激了PtdIns4,5P2、PtdIns、PtdEtn和CL中32P的掺入。在这些条件下，LH刺激的孕烯醇酮生成被完全抑制，但25-羟基胆固醇依赖性孕烯醇酮生成未受抑制。从分离的线粒体和完整细胞获得的结果表明，多磷酸化磷脂水平的升高与线粒体孕烯醇酮生成的增加并不一致相关。这表明多磷酸化磷脂在肿瘤性睾丸间质细胞中胆固醇侧链裂解活性的激素调节中不起重要作用。
