Kinetics of cell replacement in the stratum granulosum of mouse tongue epithelium

Sheet preparations of the stratum granulosum from the epithelium of the ventral surface of mouse tongue permit examination of cell replacement of this maturation compartment of the tissue. The cell transit rate/day is related to the cell desquamation rate and the cell production rate. The latter is approximately 6500-8000 cells/mm2/day, suggesting a 4-5-fold greater turnover compared with mouse dorsal skin epithelium. The use of [3H]IUdR and [3H]TdR at different times of day provides evidence for a reutilization of label from [3H]TdR released during nuclear degradation in the stratum granulosum. Flooding with unlabelled thymidine is not effective in suppressing this reutilization.