THE TRANSPORT OF PHOSPHATE BETWEEN THE PLASMA AND DIALYSATE COMPARTMENTS IN PERITONEAL-DIALYSIS IS INFLUENCED BY AN ELECTRIC-POTENTIAL DIFFERENCE

Six kinetic models of transperitoneal phosphate transport were formula ted and validated on the basis of experimental results obtained from 2 2 non-diabetic patients undergoing peritoneal dialysis, The models wer e designed to elucidate the presence or absence of diffusive, non-lymp hatic convective, and lymphatic convective phosphate transport. Calcul ations allowed for a 20% protein binding of phosphate. The validation procedure demonstrated that only diffusive and non-lymphatic convectiv e phosphate transport mechanisms were identifiable. A lymphatic convec tive phosphate transport mechanism was not identifiable, Furthermore, it was demonstrated that the electro-chemical gradient between plasma water and dialysate favours the diffusive phosphate transport, and bot h electric and chemical potentials must be taken into account in calcu lations of the transperitoneal phosphate transport.