THE ACTIVITY OF LACTATE DEHYDROGENASE AND CONTENT OF LACTATE AND PYRUVATE IN THE SCELETAL MUSCLE OF RAT UNDER CONDITIONS OF TOXIC INJURY WITH ACETAMINOPHEN

Abstract

The aim of this work was to study the activity of lactate dehydrogenase, the content of lactate, pyruvate and the lactate/pyruvate ratio in skeletal muscles of rats under the conditions of toxic damage with acetaminophen against the background of protein deficiency. Lactate dehydrogenase activity was determined by a kinetic method based on the reduction of pyruvate in the presence of NADH, lactate content – spectrophotometrically at λ 390 nm by the accumulation of iron lactate, pyruvate content – spectrophotometrically at λ 440 nm by the formation of hydrazone during the interaction of pyruvic acid with 2,4 dinitrophenylhydrazine. The study was conducted on 4 groups of animals: Group I - control animals (K); II – rats kept on a low-protein diet (LPR); III – animals with acute toxic damage by acetaminophen (TD); IV – rats, which were simulated acute toxic damage with acetaminophen (LPR/TD) against the background of a low-protein diet. It was established that under the conditions of consumption of a low-protein diet, there are no significant changes in the activity of lactate dehydrogenase and the content of lactate, while at the same time, under the studied conditions, the content of pyruvate in the cytosol of skeletal muscles decreases, which probably indicates the transformation of pyruvate in other metabolic pathways. Under the conditions of toxic damage by acetaminophen, regardless of the provision of protein in the diet, an increase in the activity of lactate dehydrogenase is accompanied by a pronounced accumulation of lactate against the background of a decrease in the content of pyruvate, which may indicate the activation of anaerobic processes of ATP formation. The results of the studies showed an increase in the lactate/pyruvate ratio in the cytosol of skeletal muscles of rats with acetaminophen-induced toxic damage against the background of dietary protein deficiency. The obtained results regarding the activity of lactate dehydrogenase, the content of lactate and pyruvate in the skeletal muscles of rats under conditions of toxic damage against the background of alimentary protein deficiency indicate the activation of anaerobic mechanisms of energy supply and can be considered as adaptive reactions aimed at maintaining energy homeostasis.