(A) Dex-induced apoptosis. Mouse thymocytes incubated for 18 hours with or without different doses of Dex (10−7 to 10−12 mol/L), were processed for DNA content analysis by propidium iodide staining. Nuclei were analyzed with a FACScan cytofluorymeter (Becton Dickinson, Mountain View, CA). Percentage numbers of hypodiploid nuclei are reported for each condition. Data shown are representative of one out of four experiments. (B) Ceramide generation after Dex treatment. Thymocytes were treated with Dex at indicated doses for 15 minutes. Lipids were then extracted, subjected to DAG kinase assay, and separated by TLC. Radioactive spots were visualized by autoradiography, scraped from the plate, and counted by scintillation counting. Data shown are representative of one out of three experiments. (C) Quantitative results for ceramide-1-phosphate levels, expressed as picomoles/106 cells. Mean values of three different experiments in duplicate are reported. Standard deviations <10% of the mean values are omitted for clarity.
