大鼠肾脏S3近端小管中果糖转运体GLUT5的存在。
Presence of fructose transporter GLUT5 in the S3 proximal tubules in the rat kidney.
作者信息
Sugawara-Yokoo M, Suzuki T, Matsuzaki T, Naruse T, Takata K
机构信息
Third Department of Internal Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan.
出版信息
Kidney Int. 1999 Sep;56(3):1022-8. doi: 10.1046/j.1523-1755.1999.00635.x.
BACKGROUND
Fructose is a nutrient as well as a potent agent for the formation of advanced glycation end product in diabetes. GLUT5 is a facilitated-diffusion fructose transporter expressed in the small intestine and kidney. Previous reports on the localization of GLUT5 by in situ hybridization and immunohistochemistry were controversial.
METHODS
The expression of GLUT5 was checked by reverse transcription-polymerase chain reaction and Southern blotting and immunoblotting analyses. Localization of GLUT5 was visualized by high-resolution immunofluorescence and immunogold electron microscopy.
RESULTS
We were able to confirm the expression of GLUT5 in the kidney. GLUT5 was predominantly present in the outer stripe of the outer medulla, where it was localized in the S3 proximal tubule cells. Double labeling with phalloidin showed that GLUT5 was localized in the brush border of the S3 proximal tubule cells. Ultrastructural examination revealed that GLUT5 was present along the plasma membrane of the apical microvilli.
CONCLUSION
GLUT5 is present at the apical plasma membrane of S3 proximal tubule cells and may serve as the transporter of fructose.
背景
果糖既是一种营养物质，也是糖尿病中晚期糖基化终产物形成的强效因子。葡萄糖转运蛋白5（GLUT5）是一种在小肠和肾脏中表达的易化扩散型果糖转运体。以往通过原位杂交和免疫组织化学对GLUT5定位的报道存在争议。
方法
通过逆转录聚合酶链反应、Southern印迹和免疫印迹分析检测GLUT5的表达。通过高分辨率免疫荧光和免疫金电子显微镜观察GLUT5的定位。
结果
我们能够证实GLUT5在肾脏中的表达。GLUT5主要存在于外髓质的外带，定位于S3近端小管细胞。用鬼笔环肽进行双重标记显示GLUT5定位于S3近端小管细胞的刷状缘。超微结构检查显示GLUT5存在于顶端微绒毛的质膜上。
结论
GLUT5存在于S3近端小管细胞的顶端质膜，可能作为果糖的转运体。
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