Acute pathological effects on rats of orally administered wortmannin-containing preparations and purified wortmannin from Fusarium oxysporum.

The pathological effects in rats of orally administered wortmannin, a mycotoxin produced by Fusarium oxysporum, were studied. Weanling rats were fed a wortmannin-containing fungal culture for 4 or 5 days, or were given by intragastric gavage a single, lethal dose of extracts of a wortmannin-containing fungal culture or pure toxin. Haemoglobinuria, necrosis of lymphoid tissues and death occurred in rats fed the fungal culture. Administration by gavage of extracts of the wortmannin-containing culture and of purified wortmannin produced gastric and myocardial haemorrhage. Major microscopic lesions in gavaged rats were haemorrhage in the myocardium and gastric submucosa and necrosis of lymphocytes in the thymus, spleen and gut-associated lymphoid tissue. Necrosis of gastro-intestinal epithelium was not observed. Myocardial haemorrhage was severe, often transmural, and is an unusual lesion that may aid in the diagnosis of wortmannin toxicosis.