Distribution and excretion of [14C]fumonisin B1 in male Sprague-Dawley rats.

[14C]Fumonisin B1 was biosynthetically produced by the addition of [14C]methyl methionine to a liquid culture of Fusarium moniliforme. The labeled toxin was then administered to rats intragastrically in one study and intravenously in another. The rats were killed at intervals up to 96 hr after dosing. In a third study, rats were dosed intragastrically 3 times at 24 hr intervals, and killed at intervals up to 144 hr after the first dose. After intragastric administration, up to 80 percent of the radiolabel was recovered in feces and up to 3% in urine. The remainder of the radioactivity was distributed in tissues, with the liver, kidney, and blood having the highest percentages. The radioactivity appeared to persist in these tissues for the duration of the experiment. This observation was duplicated in rats dosed intravenously, as well as the fact that urinary excretion of systemic [14C]fumonisin B1 takes place. Also observed during the intravenous study was the elimination of up to 35% of the radiolabel in feces, indicating that fumonisin B1 and/or its metabolites undergoes biliary excretion. The results obtained suggest a portion of the fumonisin B1 that is absorbed is persistent in the target organs, liver and kidney, for up to 96 hr.