Howell T W, Gomperts B D
Biochim Biophys Acta. 1987 Feb 18;927(2):177-83. doi: 10.1016/0167-4889(87)90132-7.
Rat peritoneal mast cells have been permeabilised by treatment with streptolysin O which generates membrane lesions of macromolecular dimensions. In the presence of Ca2+ buffered at concentrations in the micromolar range, the permeabilised mast cells release histamine, beta-N-acetylglucosaminidase and lactate dehydrogenase. Release of the two secretory components (but not lactate dehydrogenase) has an obligatory requirement for a nucleoside triphosphate and micromolar concentrations of Ca2+. Inosine triphosphate (ITP) supports the release reaction better than ATP does. It is concluded that the secretory materials are released from the cells by an exocytotic mechanism, while lactate dehydrogenase leaks from the cells through the toxin-generated lesions. By initially withholding and then supplying Ca2+ to the permeabilised cells, it is shown that the exocytotic secretory reaction can persist even when the cytosol is depleted of the bulk of soluble proteins. The streptolysin O treated mast cell preparation represents a simplified system with which to study the mechanism of exocytosis.
用链球菌溶血素O处理大鼠腹膜肥大细胞，使其通透性增加，该毒素会造成大分子尺寸的膜损伤。在微摩尔浓度范围内缓冲的Ca2+存在下，通透性增加的肥大细胞会释放组胺、β-N-乙酰氨基葡萄糖苷酶和乳酸脱氢酶。两种分泌成分（而非乳酸脱氢酶）的释放必然需要三磷酸核苷和微摩尔浓度的Ca2+。三磷酸肌苷（ITP）比三磷酸腺苷（ATP）更能支持释放反应。得出的结论是，分泌物质通过胞吐机制从细胞中释放出来，而乳酸脱氢酶则通过毒素造成的损伤从细胞中泄漏。通过先不给通透性增加的细胞提供Ca2+，然后再提供Ca2+，结果表明，即使胞质溶胶中的大部分可溶性蛋白质被耗尽，胞吐分泌反应仍能持续。经链球菌溶血素O处理的肥大细胞制剂是一种用于研究胞吐作用机制的简化系统。
