Loss of ultrafiltration during continuous ambulatory peritoneal dialysis (CAPD) is often caused by the structural peritoneal membrane alteration, namely the disappearance of mesothelial cells and the proliferation of peritoneal collagen fibers. The interleukin hypothesis has been proposed to explain the etiology of peritoneal fibrosis. The CAPD procedure has been shown to induce macrophages and lymphocytes in the peritoneum, resulting in the production of interleukin-1 (IL-1) and interferon-gamma (IFN-gamma), which may be promote to the development of peritoneal fibrosis. On the other hand, the mesothelial defect can be rapidly restored by proliferation of mesothelial cells implanted on the wound surface. In this study, we demonstrated that IL-1 beta, IFN-gamma, epidermal growth factor (EGF) and platelet derived growth factor (PDGF) enhance to the growth of cultured human peritoneal mesothelial (CHPM) cells. The cell cultures were derived from surgically removed omentum using the enzymatic disaggregation method. CHPM cells were cultured with Ham's F-12 medium containing 10% FCS up to third generation. At a concentration of 1x10(4) cells/well were cultured with various concentrations of IL-1 beta, IFN-gamma, EGF, PDGF and IL-6. [3H] TdR (37MBq/well) was added to the cultures during the last 12hr of the 48hr culture period and then radioactivity was measured to determine the uptake of [3H] TdR. It was shown that IL-1 beta, IFN-gamma, EGF and PDGF induced the proliferation of CHPM cells in a dose dependent manner when cultured in medium containing 3% FCS.(ABSTRACT TRUNCATED AT 250 WORDS)