Enzyme studies in the myopathic duck.

Abstract

There is a correlation between the effect of ouabain upon membrane ATPase activity and muscle abnormality of the white Pekin duck. Membrane preparations (sarcoplasmic reticulum) and haemolyzed erythrocytes from normal animals showed a characteristic transport ATPase activity which was inhibited by 10-4M concentration of the cardiac glycoside, ouabain. Identical preparations from myopathic animals were stimulated rather than inhibited by the same concentration of ouabain. We have interpreted this observation to indicate that the myopathy has a generalized character recognizable in erythrocytes as well as in muscle cells and that the defect itself can be associated with membrane integrity which affects the properties of the transport enzyme. Aldolase levels have been found to be higher in myopathic animals than in normal animals in serum and subcellular fractions. Although hexokinase levels in serum were not different in experimental and control animals, the subcellular compartment activities were greatly different. Creatine phosphokinase levels in serum were identical in normal and experimental animals but the mitochondrial phosphokinase activity of the myopathic birds was greatly elevated. It appears that a pronounced abnormality of carbohydrate metabolism can be correlated with this form of myopathy. Relationships of the myopathy of this experimental animal to the human malady have been considered.