Activities of cathepsins B and L in isolated nephron segments from proteinuric and nonproteinuric rats.
Activities of cathepsins B and L in isolated nephron segments from proteinuric and nonproteinuric rats.
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蛋白尿和非蛋白尿大鼠分离肾单位片段中组织蛋白酶 B 和 L 的活性。
DOI：
10.1152/ajprenal.1986.250.6.f1055
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Tisher,CC
中科院分区：
文献类型：
--
作者：
Olbricht,CJ;Cannon,JK;Garg,LC;Tisher,CC
测定了大鼠肾细胞显微解剖段溶酶内体蛋白酶组织蛋白酶B和L的含量。Z-Arg-Arg-NMec作为组织蛋白酶B的底物，z - ph - arg - nmec共同作为组织蛋白酶B和L的底物。个人S1、S2和S3段近端小管、TDL, MTAL, CTAL, DCT, CCD,从年轻女性和OMCD解剖老鼠体重130 + / - 11 g蛋白排泄较低(0.68 + / - 0.1毫克/ 24小时),从老年雌性大鼠体重289 + / - 9 g蛋白排泄10 + / - 6.3毫克/ 24小时,从年长的雄性老鼠体重404 + / - 11 g蛋白排泄22 + / - 6毫克/ 24 h,从雌鼠体重198 + / - 10 g albumin-induced蛋白尿(411 + / - 134毫克/ 24小时),体重203 +/- 11 g的雌性大鼠蛋白排泄量较低（2.7 +/- 0.4 mg/24 h）。组织蛋白酶活性沿肾元的分布相似。在所有5个组中，S1和S2段的酶活性比其他所有区段高3倍。在S2和S3阶段，蛋白尿动物的酶活性高出2 - 3倍。这些发现表明，在蛋白尿动物中，传递到近端小管的蛋白质负荷的增加选择性地刺激了S2和S3段的组织蛋白酶活性，可能是由于蛋白质摄取的增加，组织蛋白酶B和L通过内吞作用参与溶酶体消化从肾小球滤过液中重新吸收的蛋白质。
The intralysosomal proteinases cathepsins B and L were measured in microdissected segments of rat nephron. Z-Arg-Arg-NMec served as the substrate for cathepsin B and Z-Phe-Arg-NMec for cathepsin B and L together. Individual S1, S2, and S3 segments of proximal tubules, TDL, MTAL, CTAL, DCT, CCD, and OMCD were dissected from young female rats weighing 130 +/- 11 g with low protein excretion (0.68 +/- 0.1 mg/24 h), from older female rats weighing 289 +/- 9 g with protein excretion of 10 +/- 6.3 mg/24 h, from older male rats weighing 404 +/- 11 g with protein excretion of 22 +/- 6 mg/24 h, from female rats weighing 198 +/- 10 g with albumin-induced proteinuria (411 +/- 134 mg/24 h), and from female rats weighing 203 +/- 11 g with low protein excretion (2.7 +/- 0.4 mg/24 h). The distributions of cathepsin activities along the nephron were similar. In all five groups, S1 and S2 segments had enzyme activities three times higher than in all remaining segments. In S2 and S3, enzyme activities were two to three times higher in proteinuric animals. These findings suggest that in proteinuric animals the increase in the protein load delivered to the proximal tubules selectively stimulated cathepsin activities in the S2 and S3 segments, presumably because of an increase in protein uptake, and that cathepsins B and L participate in lysosomal digestion of protein reabsorbed from the glomerular filtrate via endocytosis.