Low insulin content of large islet population is present in situ and in isolated islets
Low insulin content of large islet population is present in situ and in isolated islets
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DOI：
10.4161/isl.3.1.14132
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发表时间：
2011-01-01
期刊：
影响因子：
2.2
通讯作者：
Stehno-Bittel, Lisa
中科院分区：
文献类型：
--
作者：
Huang, Han-Hung;Novikova, Lesya;Stehno-Bittel, Lisa
胰腺中存在形态学上不同的胰岛群体在60多年前就被描述过。不幸的是，很少有人注意到胰岛亚群之间可能的功能差异，直到最近。我们证明了一个群体，小胰岛，在许多功能方面优于大胰岛上级。然而，这项工作并没有确定这些差异是固有的，还是因为隔离程序的挑战而产生的。也没有数据来解释胰岛素分泌的差异。我们利用免疫组织化学，免疫荧光，ELISA和透射电镜比较发现在分离的大鼠胰岛细胞群原位和分离后的独特特征。与大胰岛相比，小的分离胰岛的胰岛素分泌显著更高，这与小胰岛（原位）中更高的胰岛素含量/面积、分离胰岛中更高的胰岛素分泌颗粒密度和更大的胰岛素含量/体积相关。具体而言，大胰岛的核心β-细胞比外周β-细胞含有更少的胰岛素/细胞，具有更低的胰岛素颗粒密度。当胰岛素分泌以总胰岛素含量标准化时，大胰岛和小胰岛释放相同百分比的总胰岛素。在体外和原位，小胰岛的细胞/面积密度高于大胰岛。这些数据为大胰岛的胰岛素分泌较差提供了可能的解释，因为它们具有较低的总细胞密度，并且核心的β细胞含有较少的胰岛素/细胞。
The existence of morphologically distinct populations of islets in the pancreas was described over 60 years ago. Unfortunately, little attention has been paid to possible functional differences between islet subpopulations until recently. We demonstrated that one population, the small islets, were superior to large islets in a number of functional aspects. However, that work did not determine whether these differences were inherent, or whether they arose because of the challenge of isolation procedures. Nor, was there data to explain the differences in insulin secretion. We utilized immunohistochemistry, immunofluorescence, ELISA and transmission electron microscopy to compare the unique characteristics found in isolated rat islet populations in situ and after isolation. Insulin secretion of small isolated islets was significantly higher compared to large islets, which correlated with higher insulin content/area in small islets (in situ), a higher density of insulin secretory granules and greater insulin content/volume in isolated islets. Specifically, the core beta-cells of the large islets contained less insulin/cell with a lower insulin granule density than peripheral beta-cells. When insulin secretion was normalized for total insulin content, large and small islets released the same percentage of total insulin. Small islets had a higher density of cells/area than large islets in vitro and in situ. The data provide a possible explanation for the inferior insulin secretion from large islets, as they have a lower total cell density and the beta-cells of the core contain less insulin/cell.