Notes: The authors of this review article highlight the use of bioluminescence as a readout for high-throughput ADME/Tox assays. They discuss three strategies for designing bioluminescent assays, using either luciferase, ATP or luciferin substrates as the limiting reagents for a luciferase-catalyzed reaction. Reporter gene assays limit the production of luciferase by tying it to a promoter or DNA regulatory region of interest. Such assays can be used to study genes that are regulated by drugs and other xenobiotics. Bioluminescent assays in which ATP is the limiting reagent of the luciferase reaction can be designed to monitor cell viability or the activity kinases. Bioluminescent assays in which the substrate is limiting can be designed so that the activity of a particular enzyme results in the production of a luciferin substrate that can, in turn, be acted upon by luciferase. (3926)