ACTIVITY OF AMP DEAMINASE AND 5′-NUCLEOTIDASE IN THE CYTOSOLIC KIDNEY FRACTION OF RATS UNDER THE CONDITIONS OF DIFFERENT PROTEIN AND SUCROSE CONTENT IN A DIET

Aim. The goal of this work was to evaluate the activity of AMP deaminase and 5′-nucleotidase in the cytosolic kidney fraction of rats under the conditions of different protein and sucrose content in a diet./ Methods. In the study, 10-12 week old white nonlinear rats weighing 130-140 g were used. The animals were separated into solitary plastic cages and ad libitum access to water. The animals were divided into the following experimental groups (n=9): С –control; LP – animals receiving low-protein ration; HS – animals receiving high-sucrose diet; LP/HS – animals receiving low-protein high-sucrose diet. The activity of 5′-nucleotidase was evaluated based on the amount of inorganic phosphorus released in AMP hydrolysis and expressed in Pi nmol per 1 min per 1 mg protein. AMP deaminase activity was determined using spectrophotometry by monitoring the increase in optical density at λ = 265 nm every 10 s for 1 min. Results. The studies showed that in the cytosolic fraction of the kidneys of animals maintained on a low-protein diet, AMP-deaminase activity did not change significantly compared to the control. At the same time, in rats kept on a high-sucrose diet an almost 4-fold increase in AMP-deaminase activity compared with the control was found. However, in rats kept on a low-protein/high-sucrose diet AMP-deaminase activity in the kidney exceeded control values but was lower than in animals maintained on a high-sucrose diet. At the same time, we found that in rats kept on a high-sucrose diet the 5′-nucleotidase activity increased by about 2 times compared with the control, while in animals maintained on a low-protein/high-sucrose diet it reached its maximum exceeding the control by more than 2.7 times. Conclusions. The excessive consumption of sucrose against the background of alimentary protein deficiency is accompanied by an increase in AMP-deaminase and 5′-nucleotidase activity in the cytosolic fraction of rat kidneys, which can be considered as a compensatory mechanism aimed at switching metabolic ransformations in conditions of nutritional imbalance.