Peculiarities of ammonia metabolism in the liver of rats under the conditions of different nutrients content in a diet
Ukrainian Biochemical Journal
The peculiarities of the metabolic transformations of ammonia in the liver of rats under the conditions of protein deprivation and high content of sucrose in the diet were studied in the research. It has been established that animals kept on high-sucrose (group III) and low-protein/high-sucrose diet (group IV) had hyperammonemia, whereas in rats maintained under the conditions of protein deficiency in the diet (group II) the blood level of ammonia nitrogen was within normal range. The revealed
... ange. The revealed hyperammonemia in animals of the III and IV groups was accompanied by a marked decrease in the activity of mitochondrial enzymes, which provide a replenishment of the endogenous ammonia pool -glutamate dehydrogenase and monoamine oxidase, reaching the minimum values in conditions of the maintenance of animals on the high-sucrose diet. at the same time, there was a marked decrease in the activity of ammonia neutralization enzymes -carbamoyl phosphate synthetase, more significant in animals of the IV group, as well as glutamine synthetase. The obtained results allow us to conclude that the hyperammonemia revealed in animals maintained on the highsucrose diet is not related to the enhanced formation of ammonia, but to the disturbances in the processes of its detoxification in the liver. At the same time, under the conditions of alimentary protein deprivation, a decrease in the activity of the key enzymes of ammonia formation (glutamate dehydrogenase and monoamine oxidase) and neutralization (carbamoyl phosphate synthetase and glutamine synthetase) is probably due to the lack of substrates for these enzymatic reactions. The obtained research results can be used to develop a strategy for correction of the disorders of ammonia metabolism under the conditions of different content of sucrose and protein in diet. K e y w o r d s: ammonia metabolism, glutamate dehydrogenase, monoamine oxidase, carbamoyl phosphate synthetase, glutamine synthetase, nutrients.