Yokota S, Tsuji H, Kato K
J Histochem Cytochem. 1986 Jul;34(7):891-7. doi: 10.1177/34.7.3519752.
Localization of cathepsin B in rat kidney was studied using immunocytochemical techniques. Cathepsin B was purified from rat liver and antibody to it was raised in rabbits. The antibody reacted with a lysosomal extract of rat kidney to form a single precipitin line in a double-diffusion test. Immunoblot analysis of lysosomal cathepsin B of rat kidney showed two species of 29K and 25K MW. After removal of Epon, semi-thin sections of glutaraldehyde-fixed tissue were stained by the indirect immunoenzyme technique. Dark-brown reaction product, indicating the antigenic sites for cathepsin B, was found in cytoplasmic granules throughout the nephron. Staining intensity and size of the positive granules varied widely in each segment of the nephron. In the glomeruli and distal tubules, a few small cytoplasmic granules were stained. In the proximal tubules, the S1 segment exhibited many large granules which were most heavily stained, whereas the S2 and S3 segments contained few positive granules. All segments of the distal tubules showed the smallest amount of positive granules. A few positive granules were also noted in the cortical and medullary collecting tubules. Control experiments confirmed the specificity of the staining. The results indicate that the major site for cathepsin B in rat kidney is the S1 segment of the proximal tubule which is known to actively take up proteins leaked through the glomerulus.
采用免疫细胞化学技术研究了组织蛋白酶B在大鼠肾脏中的定位。从大鼠肝脏中纯化组织蛋白酶B，并在兔体内制备其抗体。该抗体与大鼠肾脏的溶酶体提取物发生反应，在双向扩散试验中形成一条单一的沉淀线。对大鼠肾脏溶酶体组织蛋白酶B的免疫印迹分析显示有两种分子量分别为29K和25K的条带。去除环氧树脂后，用间接免疫酶技术对戊二醛固定组织的半薄切片进行染色。在整个肾单位的细胞质颗粒中发现了深棕色反应产物，表明存在组织蛋白酶B的抗原位点。肾单位各节段中阳性颗粒的染色强度和大小差异很大。在肾小球和远曲小管中，有一些小的细胞质颗粒被染色。在近曲小管中，S1段有许多大颗粒，染色最深，而S2和S3段阳性颗粒较少。远曲小管各节段的阳性颗粒最少。在皮质和髓质集合小管中也发现了一些阳性颗粒。对照实验证实了染色的特异性。结果表明，大鼠肾脏中组织蛋白酶B的主要部位是近曲小管的S1段，该段已知可主动摄取通过肾小球滤出的蛋白质。
