1981 Volume 23 Issue 3 Pages 482-488
The kinetics of the lip mucosa epithelial cells of C3Hf/He mice were investigated by the autoradiography method following a single injection of 3H-thymidine. The experimental mice were sacrificed at various times after labeling and used for microscopic observations. For determination of the length of different phases in the cell cycle, the analysis of percent frequency of the labeled mitosis (PLM) was made as a function of time after the labeling. The results indicated that the length of time for each phase was 9.0 hrs for s, 4.6 hrs for G2, and 20.4 hrs for for G1 a total of 34.0 hrs (Tc). However, Brown's method for calculation of the cell cycle time, being based upon the steady state growth of cells in the basal layer, resulted in about 127.3 hrs of cell cycle time for the epithelial cells. On the other hand, results of the migration of labeled cells in the basal layer indicated that basal cells containing radioactive labels begin to leave the basal layer 20 hrs after labeling and that about 50% apparently complete their migration the pricklegranular layer within 56 hrs. These results suggest that the cyclic reproduction of cells with a lengthy cell cycle of such as 124 hrs is not likely to exist in the basal layer of the lip-mucosa epithelium.
