Giordano E, Bosco D, Cirulli V, Meda P
Department of Morphology, University of Geneva Medical School, Switzerland.
J Clin Invest. 1991 Jun;87(6):2178-85. doi: 10.1172/JCI115251.
To determine whether pancreatic B cells show a constant secretion pattern during repeated stimulations, we have used a sequential hemolytic plaque assay to monitor their individual insulin release during several successive 30-min incubations in the presence of 16.7 mM glucose. We have found that the total B cell secretion did not vary significantly in these successive glucose stimulations and that, under these conditions, the majority of B cells that were stimulated to release insulin during the first incubation also secreted during the second, third, and, when this was tested, during the fourth incubation. Similarly, most of the B cells that did not release detectable amounts of insulin during the first incubation did not secrete also during the two (or three) subsequent secretion tests. Together, the two groups of B cells that showed a constant secretory pattern, represented approximately 75% of the entire B cell population. The remaining 25% of B cells shifted from a secreting to a non-secreting state, or vice versa, from one incubation to another. These observations were made under three different time frames in which we tested single B cells as well as B cell clusters at rather different intervals. These findings support the existence of distinct B cell subpopulations differing lastingly in their ability to secrete insulin in response to glucose.
为了确定胰腺β细胞在反复刺激期间是否呈现恒定的分泌模式，我们使用了连续溶血空斑试验，以监测它们在16.7 mM葡萄糖存在下连续几次30分钟孵育期间的个体胰岛素释放情况。我们发现，在这些连续的葡萄糖刺激中，总的β细胞分泌没有显著变化，并且在这些条件下，大多数在第一次孵育期间被刺激释放胰岛素的β细胞在第二次、第三次以及（在进行测试时）第四次孵育期间也分泌胰岛素。同样，大多数在第一次孵育期间未释放可检测量胰岛素的β细胞在随后的两次（或三次）分泌测试中也未分泌。这两组呈现恒定分泌模式的β细胞加起来约占整个β细胞群体的75%。其余25%的β细胞从分泌状态转变为非分泌状态，或者反之，从一次孵育到另一次孵育发生状态转变。这些观察结果是在三个不同的时间框架下进行的，在这些时间框架中，我们以相当不同的间隔测试了单个β细胞以及β细胞簇。这些发现支持存在不同的β细胞亚群，它们在对葡萄糖作出反应时分泌胰岛素的能力上存在持久差异。
