Nephrotoxicity of Cortinarius speciosissimus: a histological and enzyme histochemical study.

The nephrotoxicity of the mushroom species Cortinarius speciosissimus was studied in the rat. Dried, homogenized mushroom was given orally via gastric tubing. The development of the kidney damage was followed by both histological and enzyme histochemical methods. The first signs of kidney damage were interstitial infiltrates occurring mainly in the outer medullary zone, observed two days after the administration of the mushroom. Focuses of inflammation, which gradually scarred, appeared after four days. Chiefly necrotic changes occurred in the tubuli of the cortical zone. Valine residue cleaving aminopeptidase disappeared from the necrotic tubuli at a noticeably greater rate than arginine residue cleaving aminopeptidase. A high activity of arginine residue cleaving aminopeptidase was observed in the inflammatory focuses located in the outer medullary zone, showing the important role of this enzyme in kidney inflammation.