Effect of intake of copper, molybdenum and sulphate on copper metabolism in the sheep: III. Studies with radioactive copper in male castrated sheep

Abstract

The effects of adding Mo + SO 4 to a diet normal in Cu were to increase direct reacting and total Cu and to decrease caeruloplasmin in plasma. Plasma from the supplemented group had an additional fraction, about 42 per cent., which was neither direct reacting Cu nor caeruloplasmin. Uptake by the tissues of 64Cu after intravenous administration was slower in the supplemented than in the control animals. The concentrations of 64Cu in the direct reacting Cu of the plasma from the supplemented sheep were always higher while those for the non-direct reacting Cu, although higher initially fell after 46 hr. to levels which were similar in both groups. It was not possible to interpret the effects of the treatment on uptake of 64Cu by the tissues in terms of fluxes of stable Cu because of the difficulty of identifying the transport form of Cu. Supplementation decreased urinary excretion of 64Cu after both oral and intravenous dosing, but increased urinary and endogenous faecal excretion of stable Cu. After oral dosing the recovery of 64Cu in the faeces was 10 per cent. higher in the supplemented group indicating a lower true availability.