[The role of ionic transporters in the long-term regulation of the water content in animal cells. The mathematical model and real lymphoid cells].

Ion and water balance as well as flux balance in the animal cell, equilibrated to anisosmotic solutions, are computed for a cell model supplied by Na,K-ATPase pump, electroconductive ion channels and symporters Na-Cl, K-Cl and NaK2Cl. It is shown how the potency of each of the principal transporters to regulate cell volume depends on such conditions as the state of other ion transporters and channels, initial ion distribution and membrane potential. The obtained data are applied to studying changes in cation and water balance in the Jurkat lymphoid cells equilibrated to hyposmotic solutions. It is concluded that a steady state volume regulation in Jurkat cells, maintained in hyposmotic media 180 mosM for up to 24 h, is achieved due mainly to non-ionic mechanisms. Under the lower osmolarity of the media, 155 mosM, the ionic cell volume regulation occurs. The increase in PCl and/or the decrease in Na-Cl symport (or its equivalent, e.g. Na/H and Cl/HCO3 exchange) are considered as the most probable cause of the long-term volume decrease in lymphoid cells.