Histochemical localization of copper in the gastrointestinal tract of the rat.

Three histochemical reactions for the localization of copper were applied to liver and different parts of the gastrointestinal tract of normal as well as of rats poisoned with a solution of copper. Variable quantities of copper were demonstrated in the livers of all the poisoned rats and in 21 out of 24 sections of jejunum. Rubeanic acid counterstained with 0.5% Cresyl violet gave the best results. Copper was not demonstrable in the livers or the gastrointestinal tract of normal rats. As the metal was concentrated in the upper jejunum, it is likely that this is the site of absorption. Detection of this metal may assist in the diagnosis of hepatolenticular degeneration.