Tag Archives: acetaminophen

Indexes of citrulline metabolism in rat liver under the toxic injury against the background of alimentary protein deficiency

H. P. Kopylchuk, I. M. Nykolaichuk, I. S. Lylyk

Yuriy Fedkovych Chernivtsi National University, Ukraine;
Institute of Biology, Chemistry and Bioresources, Chernivtsi, Ukraine;
e-mail: g.kopilchuk@chnu.edu.ua

Received: 29 May 2019; Accepted: 29 November 2019

It is known that citrulline is converted into arginine in the series of metabolic transformations. Results of our previous studies showed that acetaminophen-induced toxic injury on the background of the alimentary deprivation of protein is accompanied by a decrease in arginine level in rat hepatocytes, but citrulline liver metabolism at these conditions remains incompletely clear. In this work, the content of citrulline in the rat liver mitochondrial and cytosolic fractions and the activity of citrulline-degrading enzymes – argininosuccinate synthase and argininosuccinate lyase were investigated. It was found that in the mitochondrial fraction a maximal reduction of the citrulline levels occurred after administration of acetaminophen toxic doses regardless of the protein amount in the ration, while in the cytosolic fraction the alimentary protein deficiency was a key factor in decreasing the activity of argininosuccinate synthase and arginino-succinate lyase. The data obtained indicated the disturbances of the urea cycle functioning and explained the   decrease of L-arginine level in hepatocytes in conditions of acetaminophen-induced toxic injury against the background alimentary protein deficiency.

Rat liver arginase system under acetaminophen-induced toxic injury and protein deprivation

H. P. Kopylchuk, I. M. Nykolaichuk, O. M. Zhuretska

Yuriy Fedkovych Chernivtsi National University, Ukraine;
Institute of Biology, Chemistry and Bioresourses, Chernivtsi, Ukraine;
e-mail: kopilchuk@gmail.com

Arginase activity and L-arginine content in both cytosolic and mitochondrial fractions of rat liver cells under the conditions of toxic injury on the background of protein deprivation was studied. The most significant reduction of arginase activity in liver cells and depletion of L-arginine pool was found in rats with toxic acetaminophen-induced liver injury maintained on the ration balanced by all nutrients as well as in protein deficiency rats. It was concluded that reduction of the arginase activity in the cytosolic fraction of rat liver cells, combined with simultaneous decrease of L-arginine content, may be considered as one of the mechanisms of ornithine cycle disturbance. The decline of activity of mitochondrial isoform of arginase II, for certain, is related with activation of NO-synthase system.

Peculiarities of the free radical processes in rat liver mitochondria under toxic hepatitis on the background of alimentary protein deficiency

G. P. Kopylchuk, O. M. Voloshchuk

Yuriy Fedkovych Chernivtsi National University
Institute of Biology, Chemistry and Natural Resources, Ukraine;
e-mail: kopilchuk@gmail.com

The rate of superoxide anion radical, hydroxyl radical and hydrogen peroxide generation, the level of oxidative modification of mitochondrial proteins in the liver of rats with toxic hepatitis was investigated on the background of alimentary protein deficiency. We did not find significant increases of the intensity of free radical processes in liver mitochondria of rats maintained on the protein-deficient ration. The most significant intensification of free radical processes in liver mitochondria is observed under the conditions of toxic hepatitis, induced on the background of alimentary protein deprivation. Under these conditions the aggravation of all studied forms of reactive oxygen species generation was observed in liver mitochondria. The generation rates were increased as follows: O2 – by 1.7 times, Н2О2 – by 1.5 times, ОН – practically double on the background of accumulation of oxidized mitochondria-derived proteins. The established changes in thiol groups’ redox status of respiratory chain proteins insoluble in 0.05 M sodium-phosphate buffer (pH 11.5), and changes of their carbonyl derivatives content may be considered as one of the regulatory factors of mitochondrial energy-generating function.