Norlund R, Norlund L, Täljedal I B
Department of Histology and Cell Biology, University of Umeå, Sweden.
Diabetes. 1988 Feb;37(2):194-9. doi: 10.2337/diab.37.2.194.
Dispersed islet cells from noninbred ob/ob mice were cultured for 3 days with 3 or 20 mM D-glucose and silver stained according to Rambourg et al. Two tinctorial subsets of dark and light intracellular granules were analyzed by morphometry at the ultrastructural level. The two types of granules were similar in size and shape. However, with 3 mM glucose the dark granule cores were surrounded by larger vesicles than the light granules. With 20 mM glucose, both types of granule vesicles and cores became smaller and dark-granule cores became more rounded, compared with cultures with 3 mM glucose. The higher glucose concentration also induced a marked decrease in the number (-84%) and volume density (-90%) of dark granules. In contrast, the number of light granules increased (+60%) with maintenance of their volume density. We suggest that the dark Rambourg-positive and the light Rambourg-negative beta-cell granules are functionally distinct subsets. The dark granules are probably engaged in insulin discharge. We discuss the unclear role of the light granules with a view to previously postulated heterogeneities of the insulin granule pool and their significance for exocytosis and intracellular hormone degradation.
将非近交系ob/ob小鼠的分散胰岛细胞用3或20 mM D-葡萄糖培养3天，并根据Rambourg等人的方法进行银染。在超微结构水平上，通过形态计量学分析了深色和浅色细胞内颗粒的两个染色子集。两种类型的颗粒在大小和形状上相似。然而，在3 mM葡萄糖条件下，深色颗粒核心周围的囊泡比浅色颗粒的大。与3 mM葡萄糖培养的细胞相比，在20 mM葡萄糖条件下，两种类型的颗粒囊泡和核心都变小，且深色颗粒核心变得更圆。较高的葡萄糖浓度还导致深色颗粒的数量（-84%）和体积密度（-90%）显著降低。相反，浅色颗粒的数量增加（+60%），其体积密度保持不变。我们认为，深色的Rambourg阳性和浅色的Rambourg阴性β细胞颗粒是功能上不同的子集。深色颗粒可能参与胰岛素释放。我们结合先前假设的胰岛素颗粒池的异质性及其对胞吐作用和细胞内激素降解的意义，讨论了浅色颗粒的不明作用。
