HUMAN KIDNEY PROXIMAL TUBULES ARE THE MAIN SOURCE OF PLASMA GLUTATHIONE-PEROXIDASE
HUMAN KIDNEY PROXIMAL TUBULES ARE THE MAIN SOURCE OF PLASMA GLUTATHIONE-PEROXIDASE
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DOI：
10.1152/ajpcell.1994.266.2.c367
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发表时间：
1994-02-01
影响因子：
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通讯作者：
COHEN, HJ
中科院分区：
文献类型：
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作者：
AVISSAR, N;ORNT, DB;COHEN, HJ
细胞外（E）谷胱甘肽过氧化物酶（GPX），一种存在于血浆中的独特硒糖蛋白的合成位点尚不清楚。为了探讨肾是血浆GPX主要来源的可能性，我们检测了肾衰竭透析患者和肾切除患者肾移植前后血浆GPX活性和硒浓度。这些患者的血浆GPX活性分别为正常EGPX活性的42%、22%和180%，而血浆Se水平在正常范围内。麻醉大鼠肾切除后24小时，血浆GPX活性为零时活性的30.0 +/- 6.4%。用EGPX和细胞谷胱甘肽过氧化物酶（CGPX）cDNA探针对8种人体组织进行北方杂交分析，结果显示EGPX与CGPX的比例在肾脏中最高。肾切片cRNA原位杂交研究表明，只有近端肾小管上皮细胞和壁上皮细胞的鲍曼氏囊含有EGPX转录本。Caki-2是一种近端肾小管癌细胞系，可产生并主动分泌EGPX。总之，这些结果强烈表明，肾近端小管细胞是血浆中GPX活性的主要来源。
The sites of synthesis of extracellular (E) glutathione peroxidase (GPX), a unique selenoglycoprotein present in plasma, are not known. To investigate the possibility that the kidney is the main source for the plasma GPX, we examined GPX activities and selenium concentrations in the plasma of patients with renal failure on dialysis and nephrectomized patients before and after kidney transplantation. Plasma GPX activities in these patients were 42, 22, and 180% of normal EGPX activity, respectively, whereas plasma Se levels were within the normal range. Twenty-four hours after nephrectomy of anesthetized rats, plasma GPX activity was 30.0 +/- 6.4% of the activity at zero time. Northern hybridization analysis of eight human tissues probed with EGPX and cellular glutathione peroxidase (CGPX) cDNA revealed that the ratio of EGPX to CGPX was highest in the kidney. cRNA in situ hybridization studies on kidney slices showed that only proximal tubular epithelial cells and parietal epithelial cells of Bowman's capsule contained EGPX transcripts. Caki-2, a proximal tubular renal carcinoma cell line, makes and actively secretes EGPX. Taken together, these results strongly suggest that kidney proximal tubular cells are the main source for GPX activity in the plasma.