[On the histochemistry of xanthine dehydrogenase (author's transl)]

We have investigated the enzymes of the XDH-XOD-system by histochemical technique based on a model study for histochemical tetrazolium reduction by flavine enzymes. We have not found a reaction in native sections from liver, kidney and duodenum of adult male Wistar rats. The effectors PMS, Triton X-100 and Tween 80 were inefficient. A strong reaction was observed after a short fixation (10 min) of the sections with glutaraldehyde predominantly in the duodenal epithel cells. The intensity of the reaction was much stronger in sections of liver, kidney and duodenum by influence of the effector PMS and the detergents Triton X-100 and Tween 80. The application of the membrane technique does not show advantages in the histochemical demonstration of the XDH-XOD-system. The specificity of the reaction is discussed under the aspect of the complexity of the XDH-XOD-system shown by biochemical investigations.