1. BrdU Administration: BrdU can be administered to cells in culture or to animals via injection or drinking water. 2. Incorporation Period: Cells incorporate BrdU during the S-phase of the cell cycle. 3. Tissue Processing: Harvest tissues or cells at desired time points and fix them using an appropriate fixative. 4. DNA Denaturation: Treat the fixed tissues with acid or heat to denature the DNA, exposing the incorporated BrdU. 5. BrdU Detection: Apply a BrdU-specific antibody, followed by a secondary antibody conjugated to a detectable marker (e.g., fluorescence or enzyme). 6. Visualization: Visualize the labeled cells using appropriate microscopy or other detection methods.