Reevaluation of Congo Red Test as Reticuloendothelial System Function Test Using Tritiated Congo Red Autoradiography

Abstract

Tritiated Congo red was prepared by the gas exposure method. Analytical results obtained by thin layer chromatography and spectrophotometry indicated that the radioactive Congo red thus prepared had the same properties as the original material. The incorporation of tritiated Congo red into the RES tissues of Donryu rats was studied after intravenous injection by autoradiography and liquid scintillation counter. It was found that Congo red was taken up by Kupffer's stellate cells specifically. The uptake of stellate cells reached a maximum level at the end of 24 hours after injection. However, silver grains were not found in any of the RES cells of other organs at this time. Radioactivity was detected in various tissues. The highest level was found in kidney and followed by liver, lung, spleen, heart and large intestine in decreasing order.