Rasschaert J, Malaisse W J
Laboratory of Experimental Medicine, Erasmus Medical School, Brussels Free University, Belgium.
Int J Biochem Cell Biol. 1995 Feb;27(2):195-200. doi: 10.1016/1357-2725(94)00075-m.
The aim of the present study is to compare normal and tumoral pancreatic islet cells in terms of both the activity of selected cytosolic and mitochondrial enzymes participating to nutrient catabolism and the intrinsic properties of FAD-glycerophosphate dehydrogenase. The activity of the glycolytic enzymes hexokinase and lactate dehydrogenase was higher in tumoral (RINm5F) than normal islet cells. The opposite was seen for glutamate decarboxylase, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase, glutamate dehydrogenase, 2-ketoglutarate dehydrogenase and FAD-glycerophosphate dehydrogenase (m-GDH). These findings are consistent with the high rates of glycolysis and protein synthesis seen in tumoral islet cells compared with normal islet cells, which favour mitochondrial oxidative events associated with the catabolism of D-glucose and amino acids. The intrinsic catalytic properties of m-GDH were comparable, albeit not identical, in normal and tumoral islet cells. Since a deficiency of m-GDH in pancreatic islets may represent a contributing factor in the pathogenesis of non-insulin-dependent diabetes, it is proposed that RINm5F cells may readily yield sufficient islet m-GDH for purification and further gene cloning.
本研究的目的是比较正常和肿瘤性胰岛细胞在参与营养物质分解代谢的特定胞质和线粒体酶的活性以及FAD - 甘油磷酸脱氢酶的内在特性方面的差异。肿瘤性（RINm5F）胰岛细胞中糖酵解酶己糖激酶和乳酸脱氢酶的活性高于正常胰岛细胞。而谷氨酸脱羧酶、谷氨酸 - 草酰乙酸转氨酶、谷氨酸 - 丙酮酸转氨酶、谷氨酸脱氢酶、2 - 酮戊二酸脱氢酶和FAD - 甘油磷酸脱氢酶（m - GDH）则相反。这些发现与肿瘤性胰岛细胞与正常胰岛细胞相比糖酵解和蛋白质合成速率较高一致，这有利于与D - 葡萄糖和氨基酸分解代谢相关的线粒体氧化过程。正常和肿瘤性胰岛细胞中m - GDH的内在催化特性具有可比性，尽管不完全相同。由于胰岛中m - GDH的缺乏可能是非胰岛素依赖型糖尿病发病机制中的一个促成因素，因此有人提出RINm5F细胞可能很容易产生足够的胰岛m - GDH用于纯化和进一步的基因克隆。
