Excretion of intravenously injected copper-64 in sheep

Copper-64 was injected intravenously into three sheep. The total excretion of copper in sheep was low since only 1.4-1.7% of the dose injected was excreted during a period of 60 hrs. following the injection. It was found that the biliary system was not a main excretory pathway for copper; other routes of excretion into the gastrointestinal tract seemed to be more important. The urinary and the biliary excretion were of comparable magnitude. The activity in the bile was found to be lower than in the plasma throughout the sampling period. It is assumed that a low excretion capacity of copper in the bile of sheep may be a possible factor of importance for the high susceptibility of this species to excess of copper. (author)