Immunogold localization of high-affinity glucose transporter isoforms in normal rat kidney.
Immunogold localization of high-affinity glucose transporter isoforms in normal rat kidney.
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发表时间：
1995
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通讯作者：
C. Heilig;C. Zaloga;M. Lee;X. Zhao;B. Riser;F. Brosius;P. Cortés
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作者：
C. Heilig;C. Zaloga;M. Lee;X. Zhao;B. Riser;F. Brosius;P. Cortés
背景促进性葡萄糖转运蛋白（GLUT）具有独特的动力学特征和分布，适合于它们所驻留的组织的功能。然而，很少有人知道他们在肾脏葡萄糖代谢中的作用，以前的研究肾脏GLUT的表达已经广泛只就其mRNA水平。我们在这里提供了一个完整的分析三个葡萄糖转运蛋白亚型沿着肾单位使用敏感的免疫检测方法。实验设计收集正常大鼠肾脏，固定在多聚甲醛中，并根据需要包埋在石蜡或树脂中，用于单独GLUT亚型1、3和4的免疫金标记。通过光学显微镜评价样品，并通过高分辨率光学扫描与计算机辅助检测免疫金标记的GLUT在亚细胞水平上分析选定区域。我们描述，比较，并与当地模式的葡萄糖代谢的细胞和亚细胞表达模式，这些GLUT沿着肾单位。结果GLUT 1在Henle氏延髓粗的升支、皮质集合管和内髓集合管中表达最强。相反，GLUT 3在髓内集合管中最突出，GLUT 4在髓厚的Henle升支中最突出。所有三种GLUT均在肾小球簇中检测到，GLUT 1也在壁上皮细胞中检测到。肾小管细胞中的主要亚细胞分布为：GLUT 1为基底外侧和基底外侧/细胞质; GLUT 3为基底外侧和细胞质; GLUT 4为核周/细胞质。免疫印迹证实GLUT 1和3在特定区域表达。结论1）GLUT 1、3、4在肾小球和肾小管均有表达。2)独特的GLUT表达模式沿着肾小管表明这些亚型的独特功能作用。3)肾皮质表现出较低的标记强度的高亲和力GLUT相比，髓质，更高的葡萄糖氧化和糖酵解代谢率是由更高的GLUT标记强度。
BACKGROUND Facilitative glucose transporters (GLUT) have unique kinetic characteristics and distributions suited to the functions of the tissues in which they reside. However, little is known about their individual roles in renal glucose metabolism, and previous investigations of renal GLUT expression have been extensive only with respect to their mRNA levels. We provide here a complete analysis of three GLUT isoforms along the nephron using a sensitive immunodetection method. EXPERIMENTAL DESIGN Normal rat kidneys were harvested, fixed in paraformaldehyde, and embedded in either paraffin or resin as required for immunogold labeling of individual GLUT Isoforms 1, 3, and 4. Samples were evaluated by light microscopy and selected regions analyzed by high resolution optical scanning with computer-assisted detection of immunogold-labeled GLUT at the subcellular level. We describe, compare, and related to the local patterns of glucose metabolism the cellular and subcellular expression patterns of these GLUT along the nephron. RESULTS GLUT1 was most intensely labeled in the medullary thick ascending limbs of Henle, cortical collecting ducts, and inner medullary collecting ducts. In contrast, GLUT3 was most prominent in the inner medullary collecting ducts and GLUT4 in medullary thick ascending limbs of Henle. All three GLUT were detected in glomerular tufts, and GLUT1 was also detected in parietal epithelial cells. The predominant subcellular distributions in tubule cells were: basolateral and basolateral/cytoplasmic for GLUT1; basolateral and cytoplasmic for GLUT3; and perinuclear/cytoplasmic for GLUT4. GLUT 1 and 3 expressions were confirmed in specific regions by immunoblotting. CONCLUSIONS 1) GLUT 1, 3, and 4 are expressed in both glomeruli and renal tubules. 2) The unique GLUT expression patterns along the renal tubules suggests unique functional roles for these isoforms. 3) The renal cortex demonstrates lesser labeling intensity for the high-affinity GLUT compared with the medulla, where higher rates of glucose oxidation and glycolytic metabolism are paralleled by higher GLUT labeling intensities.