Spectrophotometric method for differentiation of cardiac and hepatic lactate dehydrogenase activities in dogs.

To differentiate the origin of high total lactate dehydrogenase (LD) activity in canine sera, a spectrophotometric method based on the preferential inhibition of cardiac LD isoenzymes by pyruvate was performed. Comparison with the electrophoretic separation of LD isoenzyme activities and determination of the hydroxybutyrate dehydrogenase-to-LD ratio indicated that the method proposed gave a better discrimination between cardiac and hepatic LD activities than did the other tests.