Hepatic pathology of the colon carcinogen, azoxymethane, in Hanford-Moore miniature pigs

Azoxymethane (AOM) is commonly used in colon carcinogenesis studies in rodents. In an attempt to develop a large animal model of human colon cancer, AOM was given to Hanford-Moore miniature pigs. Six pigs were injected intraperitoneally with a single dose of AOM of either 5, 10, 20, 40 or 55 mg per kg body weight. Within 48 h, severe signs of toxicity and death occurred in animals receiving greater than 20 mg per kg AOM. After 30 days, all surviving animals were killed and necropsied. Acute hepatic necrosis with haemorrhage was the major toxic effect of AOM in all animals receiving doses exceeding 20 mg per kg. In a second, longer-term experiment, eight pigs were injected with either 20 mg per kg AOM weekly or 10 mg per kg AOM every other week or a combination of both treatments. Chronic toxic effects were limited to the liver. No colon tumours were observed. It is concluded that this particular species demonstrates marked hepatic sensitivity to the toxic effects of AOM.