Regulation of tissue factor (TF) gene expression was studied in vivo employing a murine model system. In untreated mice, TF mRNA was detected in brain, lung, kidney, and heart by Northern blot analysis. After administration of lipopolysaccharide, steady-state levels of TF mRNA were unchanged in brain, decreased in heart, and increased in both kidney and lung. In the brain, Bergmann glia within the Purkinje cell layer of the cerebellum and neuroglia within the cerebral cortex expressed TF mRNA by in situ hybridization. Epidermal cells of the skin and tongue also expressed TF mRNA. At present, we have not identified the cell type(s) in the kidney and lung responsible for increased TF gene expression. These results demonstrate tissue- and cell-specific TF gene expression in vivo. Lipopolysaccharide-mediated increases in TF expression in the kidney and lung may promote fibrin deposition in these organs during Gram-negative sepsis.