Elfeber Katrin, Stümpel Frank, Gorboulev Valentin, Mattig Sabine, Deussen Andreas, Kaissling Brigitte, Koepsell Hermann
Institut für Anatomie und Zellbiologie der Bayerischen Julius-Maximilians-Universität, Koellikerstrasse 6, 97070 Würzburg, Germany.
Biochem Biophys Res Commun. 2004 Feb 6;314(2):301-5. doi: 10.1016/j.bbrc.2003.12.090.
By immunohistochemistry, we demonstrated the localization of the Na(+)-D-glucose cotransporter SGLT1 in capillaries of rat heart and skeletal muscle, but not in capillaries of small intestine and submandibular gland. mRNA of SGLT1 was identified in skeletal muscle and primary cultured coronary endothelial cells. The functional relevance of SGLT1 for glucose transport across capillary walls in muscle was tested by measuring the extraction of D-glucose from the perfusate during non-recirculating perfusion of isolated rat hindlimbs. In this model, D-glucose extraction from the perfusate is increased by insulin which accelerates D-glucose uptake into myocytes by increasing the concentration of glucose transporter GLUT4 in the plasma membrane. The insulin-induced increase of D-glucose extraction from the perfusate was abolished after blocking SGLT1 with the specific inhibitor phlorizin. The data show that SGLT1 in capillaries of skeletal muscle is required for the action of insulin on D-glucose supply of myocytes.
通过免疫组织化学方法，我们证实了Na(+)-D-葡萄糖共转运蛋白SGLT1在大鼠心脏和骨骼肌的毛细血管中定位，但在小肠和下颌下腺的毛细血管中未定位。在骨骼肌和原代培养的冠状动脉内皮细胞中鉴定出SGLT1的mRNA。通过在离体大鼠后肢非循环灌注期间测量灌注液中D-葡萄糖的摄取量，测试了SGLT1在肌肉中跨毛细血管壁转运葡萄糖的功能相关性。在该模型中，灌注液中D-葡萄糖的摄取量因胰岛素而增加，胰岛素通过增加质膜中葡萄糖转运蛋白GLUT4的浓度来加速D-葡萄糖摄取到心肌细胞中。在用特异性抑制剂根皮苷阻断SGLT1后，胰岛素诱导的灌注液中D-葡萄糖摄取量增加被消除。数据表明，骨骼肌毛细血管中的SGLT1是胰岛素作用于心肌细胞D-葡萄糖供应所必需的。
