Creatine kinase release and muscle changes in chronic copper poisoning in sheep

Chronic copper poisoning was induced in sheep by repeated dosing with an aqueous solution of copper sulphate. A sudden rise in the level of plasma creatine kinase (CK) occurred at haemolysis but the level returned to normal once the 'crisis' was over. The level of CK in the cerebrospinal fluid remained normal throughout the experiments. An isoenzyme study showed that the CK was liberated from muscle. Light microscopic studies failed to reveal consistent changes in muscle structure but ultrastructural changes in mitochondria, similar to those described as the earlies changes in muscle fibres in vitamin E deficiency, were seen in sheep killed during and after haemolysis. The elevations of CK levels and the mitochondrial changes were most marked in sheep that did not receive selenium and vitamin E supplements. It is suggested that the CK release at haemolysis may occur because of a transient increase in the permeability of muscle membranes which may be brought about by a number of factors such as: (a) hypoxia, (b) hypercupraemia, (c) decrease in vitamin E and/or selenium content in blood and tissues.