The acute effect of amino acid based dialysis solution on peritoneal kinetics of amino acids and plasma proteins in comparison to conventional glucose-based dialysate was studied in 9 patients with end-stage renal failure on continuous ambulatory peritoneal dialysis. Instillation of 2.6% amino acid solution resulted in raised plasma concentrations of all essential amino acids included in the dialysis fluid (p < 0.005). The amino acid solution induced an augmented leakage of plasma proteins into the dialysate at all dwell times investigated (1-8 h). After a dwell time at 8 h, the dialysate total protein increased from 2.62 ± 0.45 g with glucose dialysate to 3.85 ± 0.42 g with amino acid solution (p < 0.05). Corresponding results were obtained for pV microglobulin, albumin, transferrin, IgG, and for the non-essential amino acids alanine, citrulline, and glutamine (p < 0.025) not included in the initial amino acid composition of the dialysis fluid. During the use of amino acid based dialysis fluid, the effluent prostaglandin E2 concentration increased by more than 80% in comparison to glucose dialysate (p < 0.025). The augmented loss of proteins induced by the amino acid solution was positively correlated with increased dialysate prostaglandin E2 (r = 0.8894; p < 0.001). Peritoneal ultrafiltration was not affected by the use of amino acid based dialysate fluid. The present results indicate that amino acid based dialysis fluid enhances the peritoneal permeability for plasma proteins and amino acids, probably mediated by locally generated prostanoid