Nishikawa T, Noda M, Tamura Y, Yoshida S, Kato I
Department of Medicine, Yokohama Rosai Hospital, Kanagawa, Japan.
J Steroid Biochem Mol Biol. 1993 Aug;46(2):203-8. doi: 10.1016/0960-0760(93)90295-8.
The present experiments demonstrated that the holotoxin as well as the A- and B-subunits of cholera toxin were able to directly enhance pregnenolone synthesis when isolated intact mitochondria, prepared from bovine adrenocortical tissue, were incubated; they were not, however, able to enhance pregnenolone synthesis when the inner mitochondrial fraction was similarly incubated, suggesting that the conformational structure of mitochondria is very important for activation of cholesterol side-chain cleavage by cholera toxin. Data are also presented demonstrating that cholera toxin can enhance Ca2+ release from isolated mitochondria, while pertussis toxin could activate neither pregnenolone generation nor increase Ca2+ efflux from mitochondria. Thus it is suggested that cholera toxin may activate pregnenolone synthesis by regulating Ca2+ movement in mitochondria.
目前的实验表明，当用从牛肾上腺皮质组织制备的完整分离线粒体进行孵育时，霍乱毒素全毒素以及A和B亚基能够直接增强孕烯醇酮的合成；然而，当用类似方法孵育线粒体内部分时，它们并不能增强孕烯醇酮的合成，这表明线粒体的构象结构对于霍乱毒素激活胆固醇侧链裂解非常重要。还提供了数据表明霍乱毒素可增强从分离线粒体中释放Ca2+，而百日咳毒素既不能激活孕烯醇酮生成，也不能增加线粒体Ca2+外流。因此，提示霍乱毒素可能通过调节线粒体中Ca2+的移动来激活孕烯醇酮的合成。
