EXCRETION OF FUMONISIN B-1, HYDROLYZED FUMONISIN B-1, AND THE FUMONISIN B-1-FRUCTOSE ADDUCT IN RATS

The excretion of fumonisin B-1 (FB1), hydrolyzed FB1 (HFB1), and FB1-f ructose addition products (FB1-fructose) was determined in male Fisher 344/NHsd rats. Rats were dosed by gavage with 0.69, 6.93, or 69.3 mu mol/kg of body weight FB1, HFB1, or FB1-fructose. Excretion of unchang ed FB1, HFB1, and HFB1 after hydrolysis was determined in urine and fe ces by analytical reverse phase HPLC and fluorometric detection of the o-phthaldialdehyde derivatives. Average total FB1 backbone excretion in feces was 101, 76, and 50% of the dose for FB1, HFB1, and FB1-fruct ose, respectively. No effect of dose level was found on the percentage of the dose excreted as total FB1 after hydrolysis. FB1-fructose appe ars to be absorbed to the highest extent, followed by HFB1. FB1 appear s to be excreted nearly completely in the feces. The greater absorptio n of HFB1 may explain the greater toxicity of HFB1 compared to FB1 on a molar basis. However, the detoxification of FB1 by formation of the fructose adduct cannot be explained by reduced absorption. Average tot al FB1 backbone excretion in urine was 2.7, 5.0, and 5.3% of the dose for FB1, HFB1, or FB1-fructose, respectively.