The State of the Adenyl Nucleotide System in the Liver of Rats with Toxic Hepatitis under Conditions of Protein Deficiency

Resumo

Adenyl nucleotide levels and activity of AMP catabolism enzymes in the cytosolic liver fraction of rats with acetaminophen-induced hepatitis have been studied under different dietary protein regimens. It was found that in animals with toxic hepatitis maintained on a diet rich in protein the ATP and ADP levels decreased, while AMP levels were similar to those in control animals. At the same time, in the cytosolic liver fraction of rats with acetaminophen-induced hepatitis kept under conditions of protein deficiency, ATP and AMP pools were depleted. Changes in the adenyl nucleotides content were accompanied by altered activity of AMP catabolism enzymes, such as 5′-nucleotidase and AMP deaminase. It was found that in rats with toxic hepatitis that were fed a complete diet, AMP deaminase activity increased in comparison to the control level along with 5′-nucleotidase stimulation. At the same time, in protein-restricted rats with toxic liver damage, AMP deaminase activity decreased, while 5′-nucleotidase activity was elevated in comparison to control values. These results indicate depletion of energy sources in the liver cells of rats with acetaminophen-induced hepatitis that were fed a low-protein diet. The observed changes in the activity of AMP catabolism enzymes may be considered as one of the mechanisms that regulate the cellular energy function.