1995 年 18 巻 3 号 p. 171-180
Tissue and cellular distribution of NK341 (recombinant Cu, Zn-SOD) after intravenous administration in rats was examined by autoradiography and an immunohistochemical technique. Upon observation of the autoradiograms, NK341 was found to be distributed diffusely in well-perfused tissues (liver, heart, kidney, and lung) at 5min, and subsequently to be concentrated in the kidney cortex. Elimination of NK341 from other tissues was observed at 30min after administration. These results indicate that NK341 became localized solely in the cortex of the kidney. Radioactivity in the kidney decreased with time, but was still detected even in a small amount at 144h after administration. In order to examine NK341 distribution in more detail, we performed immunoperoxidase and acid phosphatase staining studies. In the kidney, NK341 was observed in lysosomes of proximal tubule cells, but not detected in glomeruli and other sections. Since the immunoperoxidase method, which should solely detect the antigenic NK341 protein, failed to yield positive staining at 144h after administration, the remained radioactivity in the kidney at this interval might be attributed to be the existence of metabolites. In the liver and heart, NK341 was detected in Kupffer cells and macrophages, respectively, but not in the hepatocytes or myocytes.
