Tissue and plasma activity of lactic dehydrogenase and creatine kinase in the horse.

Lactic dehydrogenase, although widely distributed in most tissues, was more highly concentrated in skeletal muscle, cardiac muscle, kidney and liver. Isoenzyme patterns showed a selective concentration of LDH5 in skeletal muscle while in the heart LDH 1 and 2 were predominant. In contrast, creatine kinase was only present in substantial concentration in skeletal and cardiac muscle. The serum concentrationof both enzymes showed a wide range of activity.