Localisation and pathology of Mortierella wolfii toxin in mice

Using 125I labelled M. wolfii toxin the site of action in mice was shown to be the kidney. Autoradiographic studies revealed the label to be localised in the proximal convoluted tubules of the kidney, where there was a marked necrosis and degeneration of the epithelium causing the tubules to become considerably distended. Although the distal and collecting tubules maintained their integrity, many contained amorphous casts. An injected dose of 1 toxic unit (10 mug protein) was sufficient to produce damage to the kidney with subsequent anaemia, azotemia and albuminuria. Other organs appeared to be essentially normal and renal failure was the probable cause of death of mice.