HETEROGENEOUS EXPRESSION OF GLUCOKINASE AMONG PANCREATIC BETA-CELLS
HETEROGENEOUS EXPRESSION OF GLUCOKINASE AMONG PANCREATIC BETA-CELLS
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DOI：
10.1073/pnas.89.7.2619
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发表时间：
1992-04-01
影响因子：
11.1
通讯作者：
MAGNUSON, MA
中科院分区：
文献类型：
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作者：
JETTON, TL;MAGNUSON, MA
使用免疫细胞化学技术确定了葡萄糖激酶（GK）（胰岛葡萄糖敏感机制的关键组成部分）的细胞定位。 在大鼠胰岛中，仅在β细胞中检测到GK免疫反应性，在α、δ或含胰多肽（PP）细胞中未检测到免疫反应性。 然而，在各种β细胞，GK免疫反应性变化很大。 大多数β细胞显示相对较低水平的胞质免疫反应性，而其他β细胞强烈染色的这种酶。 GK和GLUT2（β细胞的高K（m）葡萄糖转运蛋白）的共定位研究证实，这些蛋白质位于β细胞的不同亚细胞结构域。 胰岛中胰高血糖素和生长抑素分泌细胞中缺乏GK免疫反应性表明这些细胞不直接对葡萄糖产生反应或利用根本不同的机制来感知葡萄糖波动。 此外，胰腺β细胞中GK的差异表达表明葡萄糖磷酸化可能是这些细胞功能多样性的酶促控制点。
The cellular location of glucokinase (GK), a key component of the glucose-sensing mechanism of the pancreatic islet, was determined using immunocytochemical techniques. In rat islets, GK immunoreactivity was detected only in beta-cells with no immunoreactivity detected in alpha, delta, or pancreatic polypeptide-containing (PP) cells. However, within various-beta cells, GK immunoreactivity varied considerably. Most beta-cells displayed relatively low levels of cytoplasmic immunoreactivity whereas other beta-cells stained intensely for this enzyme. Colocalization studies of GK and GLUT2, the high K(m) glucose transporter of beta-cells, confirmed that these proteins are located in different subcellular domains of beta-cells. The lack of GK immunoreactivity in glucagon- and somatostatin-secreting cells in islets suggests that these cells are not directly responsive to glucose or utilize a fundamentally different mechanism for sensing glucose fluctuations. Moreover, the differential expression of GK among pancreatic beta-cells suggests that glucose phosphorylation is the probable enzymatic control point for the functional diversity of these cells.