Girard J, Postic C, Burcelin R, Guillet I, Leturque A
Centre de Recherche sur l'Endocrinologie moléculaire et le Développement, CNRS, Meudon.
Presse Med. 1992 Dec 5;21(42):2053-9.
Glucose transport is an important step in the regulation of glucose homeostasis. Two types of transport systems are described: active transport accumulates glucose in specific cells, whereas facilitative transport equilibrates blood glucose and intracellular glucose inside all mammalian cells. At the present time, different levels of facilitative transport regulation are known. Facilitative transport is achieved by 5 different isoforms; each isoform has its own characteristics and is subjected to tissue-specific regulation. Alteration of glucose transporters expression may be involved in a physiopathological situation such as diabetes which is characterized by insulin resistance of peripheral tissues and impaired insulin secretion by beta pancreatic cells. Thus, Glut 2 expression is reduced in the beta cells of diabetic rats. The reduction of Glut 2 expression correlates with, and may contribute to the loss of glucose-stimulated insulin secretion. However, Glut 2 expression in liver remains unaltered. The insulin resistance of peripheral tissues may be explained in adipose tissue by a decrease in Glut 4 expression. In skeletal muscle, Glut 4 expression remains constant whatever the physiological or physiopathological situation.
葡萄糖转运是调节葡萄糖稳态的重要步骤。已描述了两种类型的转运系统：主动转运在特定细胞中积累葡萄糖，而易化转运使所有哺乳动物细胞内的血糖和细胞内葡萄糖达到平衡。目前，已知易化转运调节的不同水平。易化转运由5种不同的同工型实现；每种同工型都有其自身的特点，并受到组织特异性调节。葡萄糖转运蛋白表达的改变可能参与了诸如糖尿病等生理病理情况，糖尿病的特征是外周组织的胰岛素抵抗和胰腺β细胞胰岛素分泌受损。因此，糖尿病大鼠的β细胞中Glut 2表达降低。Glut 2表达的降低与葡萄糖刺激的胰岛素分泌丧失相关，并且可能是其原因之一。然而，肝脏中的Glut 2表达保持不变。外周组织的胰岛素抵抗在脂肪组织中可能通过Glut 4表达的降低来解释。在骨骼肌中，无论生理或病理生理情况如何，Glut 4表达都保持恒定。
