Excretion and tissue distribution of radioactivity from aflatoxin B1-14-C in rats.

Abstract

Summary Excretion patterns of 14C derived from intraperitoneal doses of ring-labeled and methoxy-labeled aflatoxin B1 were investigated in male rats. It was found that 70–80% of the administered radioactivity from both compounds was excreted during the 24 hours following administration. A major excretory route of the ring-labeled material was through biliary excretion into feces, which accounted for nearly 60% of the administered 14C. A further 20% was excreted in urine, and only negligible amounts in CO2. In contrast, approximately 25% of administered radioactivity from the methoxy-labeled compound appeared in CO2 with a concomitant decrease in feces. These results indicate that O-demethylation represents a significant metabolic pathway for aflatoxin B1 in the rat. Radioactivity derived from ring-labeled compound was present at maximum levels in liver and kidneys 0.5 hour after administration, with small amounts present in other organs. The concentration of radioactivity was five to fifteen times greater in liver than in other tissues, and at the end of 24 hours, the liver contained an amount equal to the content of the remainder of the carcass. This finding is associated with the relative tissue specificity of aflatoxin B1 as a hepatotoxin.