Measurements of cytoplasmic Ca2+ in islet cell clusters show that glucose rapidly recruits beta-cells and gradually increases the individual cell response.
Measurements of cytoplasmic Ca2+ in islet cell clusters show that glucose rapidly recruits beta-cells and gradually increases the individual cell response.
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胰岛细胞簇中细胞质 Ca2+ 的测量表明，葡萄糖快速招募 β 细胞并逐渐增强单个细胞的反应。
作者：
F. Jonkers;J. Henquin
发生代谢、生物合成或分泌反应的分离的单个β细胞的比例随着葡萄糖浓度而增加（募集）。目前尚不清楚当β细胞偶联时，募集是否在原位持续。因此，我们测量了培养1-2天的小鼠胰岛单细胞或细胞簇中的细胞质游离Ca 2+校正（[Ca 2 +]i）（葡萄糖诱导的胰岛素分泌的触发信号）。在单个细胞中，阈值葡萄糖浓度范围在6和10 mmol/l之间，在该浓度下达到最大约65%的响应细胞。只有13%的细胞对葡萄糖加甲苯磺丁脲没有反应。在6和10 mmol/l葡萄糖之间，显示[Ca 2 +]i升高的簇的比例从约20%增加到95%，表明簇之间对葡萄糖的阈值敏感性不同。在响应簇内，75%的细胞在6 mmol/l葡萄糖下有活性，在8-10 mmol/l葡萄糖下有95-100%的细胞有活性，表明单个细胞募集在簇内并不突出;在对葡萄糖响应的簇中，所有或几乎所有细胞都参与了响应。独立的细胞招聘，葡萄糖逐渐增加的幅度的平均[Ca 2 +]i上升，在个别细胞，无论是孤立的或相关的集群。当胰岛素分泌与[Ca 2 +]i同时测量时，发现两个事件之间具有良好的时间和定量相关性。然而，β细胞募集在10 mmol/l葡萄糖时达到最大，而胰岛素分泌增加至15-20 mmol/l葡萄糖。总之，葡萄糖引起的β细胞募集可发生在[Ca 2 +]i反应阶段。然而，这种类型的募集仅限于一个狭窄的葡萄糖浓度范围，特别是当β细胞缔合降低反应的异质性时。因此，葡萄糖诱导的胰岛胰岛素分泌不能完全归因于β细胞的募集以产生[Ca 2 +]i反应。调节[Ca 2 +]i反应的幅度和Ca 2+对胞吐作用的作用（葡萄糖的放大作用）可能更重要。
The proportion of isolated single beta-cells developing a metabolic, biosynthetic, or secretory response increases with glucose concentration (recruitment). It is unclear whether recruitment persists in situ when beta-cells are coupled. We therefore measured the cytoplasmic free Ca2+ correction ([Ca2+]i) (the triggering signal of glucose-induced insulin secretion) in mouse islet single cells or clusters cultured for 1-2 days. In single cells, the threshold glucose concentration ranged between 6 and 10 mmol/l, at which concentration a maximum of approximately 65% responsive cells was reached. Only 13% of the cells did not respond to glucose plus tolbutamide. The proportion of clusters showing a [Ca2+]i rise increased from approximately 20 to 95% between 6 and 10 mmol/l glucose, indicating that the threshold sensitivity to glucose differs between clusters. Within responsive clusters, 75% of the cells were active at 6 mmol/l glucose and 95-100% at 8-10 mmol/l glucose, indicating that individual cell recruitment is not prominent within clusters; in clusters responding to glucose, all or almost all cells participated in the response. Independently of cell recruitment, glucose gradually augmented the magnitude of the average [Ca2+]i rise in individual cells, whether isolated or associated in clusters. When insulin secretion was measured simultaneously with [Ca2+]i, a good temporal and quantitative correlation was found between both events. However, beta-cell recruitment was maximal at 10 mmol/l glucose, whereas insulin secretion increased up to 15-20 mmol/l glucose. In conclusion, beta-cell recruitment by glucose can occur at the stage of the [Ca2+]i response. However, this type of recruitment is restricted to a narrow range of glucose concentrations, particularly when beta-cell association decreases the heterogeneity of the responses. Glucose-induced insulin secretion by islets, therefore, cannot entirely be ascribed to recruitment of beta-cells to generate a [Ca2+]i response. Modulation of the amplitude of the [Ca2+]i response and of the action of Ca2+ on exocytosis (amplifying actions of glucose) may be more important.
影响因子：
3.7
作者：
SALOMON, D;MEDA, P
通讯作者：
MEDA, P