Metabolism of Aflatoxin B ! in Rhesus Monkeys

The metabolism of aflatoxin B, has been investigated in male rhesus monkeys given i.p. injections of a mixture of ring-labeled aflatoxin B!-'4C and nonradioactive toxin, at a total dose of 0.4 mg/kg. Thirty-five % of the administered radioactivity was excreted in urine within 96 hr. The excretion rate reached a maximum 1 hr after dosing and then fell rapidly, but urine excreted after 96 hr still contained detectable radioactivity. A new method for isolation and identification of urinary aflatoxin metabolites was devised. Of the total urinary metabolites, only 12 to 15% were chloroform extractable, including at least 3 fluorescent metabolites of unknown structure in addition to aflatoxins B! and MI. Chloroforminsoluble metabolites were isolated on an Amberlite XAD-2 column and separated by a DEAE-Sephadex A-25 column into 6 subfractions. The major subfraction (60%) was hydrolyzed almost quantitatively by ß-glucuronidaseand the liberated metabolite was identified as aflatoxin Pj, the 0-demethylation product of aflatoxin B! . Aflatoxin P, in urine represented approximately 20% of the administered dose, 17% as glucuronide, 3% "as sulfate, and 1% as