Infiltration of leukocytes and mononuclear cells into the glomeruli is an early pathological finding in human and experimental glomerulonephritis. However, the cellular and molecular basis for cell infiltration into the glomeruli is not yet completely understood. In addition, there is little information on the expression of intercellular adhesion molecule-1 (ICAM-1) on glomerular cells. In the present study, we investigated the expression of ICAM-1 on cultured bovine glomerular endothelial cells (GEN) and its regulation by the pro-inflammatory cytokines, interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1) and lipopolysaccharide (LPS). Immunocytochemical staining showed that ICAM-1 molecules were constitutively expressed on the surface of GEN. In flow cytometric and ELISA analyses, ICAM-1 molecule expression on GEN was significantly upregulated by IL-1 beta, MCP-1 and LPS in a dose-dependent manner, but not by IL-6. LPS was the most potent inducer of ICAM-1 molecule expression on GEN. The effects of IL-1 beta, MCP-1 and LPS were observed as early as 4 h and reached a maximal level by 18 h. These results suggest that ICAM-1 on GEN can participate in the infiltration of mononuclear cells into glomeruli in human and experimental glomerulonephritis.