The influence of calmodulin on steroid synthesis in leydig cells from rat testis.
The influence of calmodulin on steroid synthesis in leydig cells from rat testis.
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DOI：
10.1210/endo-109-5-1677
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发表时间：
1981-11
期刊：
影响因子：
4.8
通讯作者：
Peter F. Hall;Shoji Osawa;James J. Mrotek
中科院分区：
文献类型：
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作者：
Peter F. Hall;Shoji Osawa;James J. Mrotek
为了研究钙调素在调节间质细胞合成睾酮中的可能作用，采用了两种方法：三氟拉嗪作为钙调素的抑制剂，脂质体将钙调素递送到细胞中。该抑制剂阻止了间质细胞对LH和cAMP的预期反应。首先，当这些药物被添加到间质细胞时，睾酮合成的增加被药物抑制了。其次，由LH和cAMP产生的胆固醇向线粒体的转运增加被三氟拉嗪抑制。第三，这些药物在分离的线粒体中产生的增加的胆固醇侧链切割（胆固醇导致孕烯醇酮）也被药物抑制。当间质细胞与含有钙调素的脂质体孵育时，睾酮的产生、胆固醇向线粒体的运输以及胆固醇侧链的裂解都受到刺激。钙调蛋白的作用，如果钙调蛋白在加入脂质体之前加入，比钙调蛋白和Ca2+从单独的脂质体引入间质细胞更大。如果钙调素透析对抗EGTA，如果钙调素与过量的抗钙调素存在于脂质体中，如果钙调素或Ca2+被添加到培养基中（没有脂质体），或者Ca2+单独存在于脂质体中，则不会发生睾酮合成的刺激。这些观察结果表明，钙调素参与调节胆固醇到线粒体的运输，这一过程是由LH和cAMP刺激的，这可能是这些药物产生的类固醇合成增加的原因。
Two approaches were used to study the possible role of calmodulin in the regulation of synthesis of testosterone by Leydig cells: trifluoperazine was used as an inhibitor of calmodulin and liposomes were used to deliver calmodulin into the cells. The inhibitor prevented the expected responses of Leydig cells to LH and to cAMP. First the increase in synthesis of testosterone produced when these agents are added to Leydig cells was inhibited by the drug. Second, increased transport of cholesterol to mitochondria produced by LH and cAMP was inhibited by trifluoperazine. Third, increased side-chain cleavage of cholesterol (cholesterol leads to pregnenolone) produced by these agents in isolated mitochondria was also inhibited by the drug. When Leydig cells were incubated with liposomes containing calmodulin, production of testosterone, transport of cholesterol to mitochondria, and side-chain cleavage of cholesterol were all stimulated. The effect of calmodulin is greater if Ca2+ is added before incorporation into liposomes than if calmodulin and Ca2+ are introduced into the Leydig cells from separate liposomes. Stimulation of testosterone synthesis does not occur if calmodulin is dialyzed against EGTA, if calmodulin with excess anticalmodulin is present in the liposomes, if either calmodulin or Ca2+ is added to the medium (no liposomes), or if Ca2+ alone is present in liposomes. These observations suggest that calmodulin is involved in regulating the transport of cholesterol to mitochondria, a process that is stimulated by LH and cAMP and one that may account for the increased steroid synthesis produced by these agents.