PATHWAY OF INSULIN IN PANCREATIC TISSUE ON ITS RELEASE BY THE B-CELL
PATHWAY OF INSULIN IN PANCREATIC TISSUE ON ITS RELEASE BY THE B-CELL
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DOI：
10.1152/ajpgi.1993.264.2.g187
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发表时间：
1993-02-01
影响因子：
--
通讯作者：
BENDAYAN, M
中科院分区：
文献类型：
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作者：
BENDAYAN, M
应用蛋白a金免疫细胞化学方法发现胰岛素在大鼠胰腺细胞外间隙和毛细血管中存在。在b细胞排出时，胰岛素在细胞外空间扩散，并与所有胰腺细胞的质膜相互作用。对于b细胞，与平面结构域相比，间质微绒毛质膜结构域被优先标记。相比之下，腺泡细胞基底质膜的指状区和平面区被同样标记。在内皮细胞中，窗区标记优于高细胞质区，窗、管腔和管腔质膜被标记。细胞质区有明显的细胞质囊泡标记；细胞间连接则没有。这些结果表明，在与膜结合后，胰岛素通过开孔和囊泡系统在毛细血管中转移。从胰岛到胰岛周围，再到远端胰岛区域，内皮下空间和毛细血管中的胰岛素水平显著下降，这表明胰岛素在胰岛组织中的高水平，随着胰岛素在胰岛内外循环而迅速下降。因此，胰腺细胞暴露在高水平的胰岛素中，胰岛素水平因区域而异，可能导致腺泡实质在地形上划分为岛周和岛端组织。
Insulin was revealed in the extracellular space and blood capillaries of the rat pancreas by applying protein A-gold immunocytochemistry. On the discharge by the B-cell, insulin diffuses in the extracellular space and interacts with the plasma membrane of all pancreatic cells. For the B-cell, the interstitial microvillar plasma membrane domain was preferentially labeled compared with the flat domain. In contrast, the digitations and flat domains of the basal plasma membrane of the acinar cells were equally labeled. In the endothelium, the labeling was superior in fenestrated areas than in the high cytoplasmic ones, the fenestrae, the luminal and abluminal plasma membranes being labeled. In the cytoplasmic areas the plasmalemmal vesicles were significantly labeled; the intercellular junctions were not. These results indicate that upon binding to the membrane, the transfer of insulin across the capillaries occurs through both the fenestrations and the vesicular system. The labeling of insulin in the subendothelial space and blood capillaries decreased significantly from the insular to the peri-insular and further to the teleinsular regions, demonstrating that insulin levels, high in insular tissue, decrease very rapidly as insulin circulates through and out of the pancreas. The pancreatic cells are thus exposed to very high levels of insulin that vary according to the regions, probably contributing to the topographical partition of the acinar parenchyma into peri-insular and teleinsular tissues.