Biliary excretion of exogenous cadmium and manganese in Long-Evans Cinnamon (LEC) rats characterized by an inherently gross amount of copper-metallothionein in the liver.

Long-Evans Cinnamon (LEC) rats are characterized by the sudden onset of hepatitis around 4 months after birth and the gross accumulation of hepatic copper (Cu) accompanied by metallothionein (MT). The biliary excretion of manganese (Mn) and cadmium (Cd) injected intravenously was studied in 3-month-old LEC rats without signs of hepatitis. Injected Mn was excreted into the bile in LEC and Fischer rats used for comparison. However, increased biliary excretion of Cd was found not in the LEC rat but in the Fischer rat. Excretion of horseradish peroxidase (HRP) injected along with the metal mixture was significantly lower in the LEC group than in the Fischer group. Our results suggest that Mn excretion is not related to the existence of a gross amount of Cu-MT. Reduced excretion of Cd may be partly due to binding to Cu-MT in the liver. Decreased excretion of HRP implies the existence of an inherent defect in the bile excretion route for endo- and exogenous substances.