Transgene activity in an animal model of gram-negative sepsis. LPS was administered to mice (colony 32) containing a luciferase transgene under the control of the mouse GP Ibα promoter. The wide range of LPS-induced effects and toxicity in mice is well documented and doses administered to individual mice were sufficient to achieve maximal levels for a variety of cytokines. LPS was administered by intraperitoneal injection (25 mg/kg) and luciferase activity in the major murine organs was determined. Results are shown for assays performed 24 hours postinjection, although similar results were obtained at 4-hour intervals leading up to the 24-hour assay shown. The mean and standard error of the mean are shown for each organ (n = 4). Control mice were injected intraperitoneally with an equal volume of saline buffer. No differences in the levels of luciferase activity were observed at any time point.