抄録
A method for the demonstration of the activity of purine nucleoside phosphorylase in the tissues is described. In the histochemical system, the enzyme converted the substrate inosine to hypoxanthine. The resulting hypoxanthine was oxidized by exogeneous and endogeneous xanthine oxidase to uric acid, whereby the xanthine oxidase reduced Nitro BT to insoluble formazan. The specificity of the method is discussed in this study. In addition, the distribution of the purine nucleoside phosphorylase activity in the various tissues of rats is described. High activities were found in the liver cells, reticular cells of spleen, and oocytes of ovary. Moderate activities were found in the epithelium of the choroid plexus, reticular cells of the thymus, epithelium of the bronchiole, cells of the alveolar wall, parietal cells of the gastric gland, proximal tubules of the kidney, interstitial cells of the ovary, and epithelium of the ductus epididymidis. The cardiac muscle, small intestine, and pancreas were inactive. All the activities were found in the cytoplasm and not in the nucleus.
