Urinary excretion of thiol conjugates of aflatoxin B1 in rats and hamsters.

After intraperitoneal injection of [3H]aflatoxin B1 in rats and hamsters, 24-h urinary excretion of aflatoxin B1 metabolites was examined in these species. Total excretion was 10-15% of the injected dose with hamster excreting 50% more than the rat. In both species, 60% of the total excretion was due to glucuronide and sulfate conjugates of hydroxy metabolites. Striking differences were observed in the excretion of both aflatoxin B1-diol and various thiol conjugates. Aflatoxin B1-glutathione and aflatoxin B1-cysteinylglycine were major thiol conjugates in rats and hamsters, respectively. An unknown metabolite believed to be mercapturic acid (N-acetylcysteine conjugate) of aflatoxin B1 was excreted by both species, hamster excreting twice as much as the rat.