In patients on long-term continuous ambulatory peritoneal dialysis (CAPD), peritoneal dysfunction is considered to be due to the loss of peritoneal mesothelial cells and to subsequent peritoneal fibrosis and neovascularization. Our aim in the present study was to clarify the role of various components of peritoneal dialysis fluid in the occurrence of peritoneal dysfunction in CAPD patients. We used a cell counting assay and ELISA to study the viability of human peritoneal mesothelial cells and their secretion of basic fibroblast growth factor (bFGF)--which induces peritoneal fibrosis and neovascularization--by cells cultured with various components of peritoneal dialysis fluid. The viability of cultured cells, ranked from highest to lowest by solution type, was bicarbonate (40 mEq/L) > lactate (15 mEq/L) + bicarbonate (25 mEq/L) > lactate (40 mEq/L). Viability also showed a concentration-dependent decrease in the presence of advanced glycation end-products of bovine serum albumin. The bFGF level in the supernatant showed a concentration-dependent increase in the presence of glucose and glycated albumin; bFGF level decreased as the bicarbonate concentration increased. Low levels of glucose, lactate, and glycated albumin, and a high concentration of bicarbonate may preserve the viability of peritoneal mesothelial cells and prevent bFGF secretion.