Specificity of organ distribution of isoenzymes of lactate dehydrogenase (LDH; EC 1.1.1.27) was studied by electrophoretic method in agar plates. Extracts of tissues of heart, kidney, skeletal muscle, liver, spleen, lungs of American mink (Mustela vison L.), Arctic fox (Alopex lagopus), silver fox (Vulpes vulpes L.), pine marten (Martes martes L.), moose (Alces alces L.), European beaver(Castor fiber L.), Canadian beaver (Castor Canadensis Kuhl), mountain hare (Lepus timidus L.) and bank vole (Clethrionomys glareolus Schreb.) were examined. In the presence of common pattern of LDH isoenzymes distribution in different organs the specific differences were revealed though. The spectrum of isoenzymes in liver tissue of mountain hare differs from the one in rodents by considerable content of LDH hybrid fractions.
Isoenzyme spectrum in the tissues of kidney, lungs, spleen and liver in moose has high content of LDH-1, which testifies to the disbalance of glycolytic processes in ruminants towards formation of piruvate, which is the basic substratum for gluconeogenesis. European and Canadian beavers being systematically closed species, have specific differences in LDH isoenzyme spectrum, which are the most pronounced in lungs and kidney.