Disturbances in Tryptophan Metabolism After a Single Dose of Aflatoxin Bl and Chronic Intoxication with Carbon Tetrachloride

Summary

Female Wistar rats were given a single dose (half the lethal dose 50) of aflatoxin 81, either alone or in combination with chronic intoxication with carbon tetrachloride (CCI₄). During a 30-month experimental period, histologic and biochemical studies were conducted. An L-tryptophan load (10 mg/100 g rat) was administered and the urinary excretion of certain of its metabolites was evaluated. The activity of hepatic tryptophan-oxygenase and the quantity of nucleic acids were determined when the animals were killed. The percentage of animals with abnormal test results was significantly higher in the groups given aflatoxin or CCl₄+aflatoxin than in a control group. Furthermore, the association of the 2 toxic substances increased all biochemical parameters and induced earlier and more intense histologic modifications. The number of hepatomas, however, was virtually identical in all groups.