Lewis C E, Clark A, Ashcroft S J, Cooper G J, Morris J F
Department of Human Anatomy, Oxford, U.K.
Mol Cell Endocrinol. 1988 May;57(1-2):41-9. doi: 10.1016/0303-7207(88)90030-5.
Hormone secretion from single, rat pancreatic B cells was visualised by a reverse haemolytic plaque assay for C-peptide. Quantitative analysis of the size and number of haemolytic plaques indicated that exposure to 3, 5, 10 and 20 mM glucose resulted in a dose-dependent increase in both the magnitude of C-peptide, and thus, insulin release by individual B cells and the recruitment of activity secreting B cells. Somatostatin and calcitonin gene-related peptide, fragment 28-37 (CGRP28-37) were shown to inhibit glucose-stimulated insulin release as assessed by the size of individual plaques and the number of recruited B cells, and hence to reduce the total area of plaques formed. In the presence of 15 mM glucose, a dose-dependent effect of CGRP28-37 on the secretion of insulin was observed, with the size of plaques formed by individual B cells reduced at concentrations of CGRP28-37 between 10(-5) and 10(-11) M. Thus, both somatostatin and CGRP28-37 can act directly on individual B cells to inhibit their secretory response to increasing levels of glucose. We suggest that these peptides which can be immunolocalised in islet cells may have a role in the regulation of insulin secretion.
通过C肽反向溶血空斑试验观察了单个大鼠胰腺β细胞的激素分泌情况。对溶血空斑大小和数量的定量分析表明，暴露于3、5、10和20 mM葡萄糖会导致单个β细胞的C肽分泌量呈剂量依赖性增加，进而胰岛素释放量增加，同时分泌活性β细胞的募集也增加。通过单个空斑大小和募集的β细胞数量评估发现，生长抑素和降钙素基因相关肽片段28 - 37（CGRP28 - 37）可抑制葡萄糖刺激的胰岛素释放，从而减少形成的空斑总面积。在15 mM葡萄糖存在的情况下，观察到CGRP28 - 37对胰岛素分泌有剂量依赖性作用，当CGRP28 - 37浓度在10^(-5)至10^(-11) M之间时，单个β细胞形成的空斑大小减小。因此，生长抑素和CGRP28 - 37均可直接作用于单个β细胞，抑制其对葡萄糖水平升高的分泌反应。我们认为这些可在胰岛细胞中进行免疫定位的肽可能在胰岛素分泌调节中发挥作用。
