A POSSIBLE ROLE OF ADENINE-NUCLEOTIDE MET ABOLISM IN THE REGULATION OF HUMAN ERYTHROCYTE VOLUME

A simplified mathematical model of cell metabolism describing ion pump s, glycolysis, and adenylate metabolism was constructed and investigat ed in order to clarify the functional role of the adenylate metabolism system in human erythrocytes. The adenylate metabolism system was sho wn to be able of functioning as a specific regulatory system stabilizi ng intracellular ion concentration and, hence, erythrocyte volume upon the changes in the cell membrane permeability. This stabilization is provided by an increase in the adenylate pool associated with the incr ease in the activity of ATPases. A proper regulation of the adenylate pool may be achieved only by the regulation of the AMP degradation or synthesis rates. The optimal rate of the adenylate metabolism in eryth rocytes ranges from several tenth of a percent to several percents of the glycolytic flux. An increase in this rate results in the deteriora tion of the cell metabolism stability. A decrease in the adenylate met abolism rate makes the Functioning of this metabolic system inefficien t, because the time necessary to achieve the stabilization of intracel lular ion concentrations becomes comparable to the erythrocyte life sp an.