Hexadecane enhances non-biliary, intestinal excretion of stored hexachlorobenzene by rats

[14C]Hexachlorobenzene (100 mg/kg) was orally administered to 4 groups of rats. Ten days later the effects of hexadecane (3 x 5 ml/kg by gavage) and/or bile duct ligation on urinary and fecal excretion and tissue levels of hexachlorobenzene were examined. Hexadecane did not affect urinary excretion of hexachlorobenzene, whereas bile duct ligation tripled it. Each of the 3 treatments (n-hexadecane, bile duct ligation and the combination of the two) resulted in a significant increase in fecal excretion of hexachlorobenzene. Moreover, the combination of hexadecane and bile duct ligation produced a greater increase in fecal excretion of hexachlorobenzene than either treatment alone. Concentrations of hexachlorobenzene in blood, fat and kidney were not affected by any of the treatments, but liver concentrations were reduced significantly by bile duct ligation. Concentrations of hexachlorobenzene in intestinal contents indicate that intestinal-wall passage is the primary route of elimination from the body and that enhancement of elimination occurs mostly distal to the jejunum.