A histochemical and immunohistochemical investigation of guanase and nedasin in rat and human tissues

Humanguanase isknownas a specific enzymeintheliver, kidney, andbrain. However, its functional significance remains poorly understood. In addition, interestingly, a different organ distribution between humans and rats was suggested. Here, we performed immunohistochemical staining with anti-human nedasin(neuronal and endocrine discs large/SAP102 associated protein), whose sequence was identical to that of guanase, antibody and histochemical staining for guanase in normal tissues of rat and human liver, kidney, and small intestine, and comparedthe results. Guanase activitywas observed uniformly in the rat hepatocytes, biliary epithelium and vascular endothelium cells, while itwas localized to the hepatocytes and biliary epithelium in the human liver. When the histochemical staining for guanase and the immunohistochemical staining for nedasin were compared, the stained regions were different in the rat liver butwere almost consistent in all human tissues. Totally consistent staining resultswere also obtained between rats and humans in the other organization except the liver. Based upon the research reports to date, the experiments on guanase and nedasin in rat organs performed in this study are considered to have important implications in the investigation of their physiological significance.