Absorption and excretion of Cu64-labeled copper by the rat

Abstract

Varying doses of Cu64-labeled cupric acetate were given orally or intravenously to adult male rats. The urinary and fecal excretion of Cu64 was measured in intact rats and in rats with obstruction of the common duct. In addition, the biliary Cu64 was assayed in rats with biliary fistula. Only about half to two-thirds of doses up to 1 µg of copper were absorbed; the site of absorption seemed to be the upper portion of the small intestine. With larger doses, the percentage absorbed fell, but the absolute amount increased. Much less copper was excreted in the feces when the rat had a biliary fistula, the difference being accounted for by the biliary Cu64. Fecal excretion was not prevented by duodenostomy below the pancreatic and biliary ducts and therefore presumably reflects excretion through the gut mucosa. Significantly more copper was excreted in the bile and in the urine when the Cu64 was given intravenously. Very little of the biliary Cu64 was absorbed from the gut of intact rats when it was given by stomach tube.