Abstract
For the purpose of studying some aspect of cell proliferation in the taste bud, rats, weighing 100 g in average, were injected with ^3H-thymidine in dosis of 1μc per gram of body weight intraperitoneally and the cells that were located in the peripheral epithelia of taste buds of papilla vallata and in the peripheral epithelia of the same papilla were studied for the distribution and kinetics of labeled cells by means of autoradiography. 1) Labeling was detected exclusively in the basal cells of epithelia of both regions by 1 hour after the injection and the radioactive indices for the peripheral epithelia of taste bud and for those on the back of the tongue amounted respectively to 30.9% and 17.7%. 2) The life span of the epithelial cells in the periphery of taste bud was grossly calculated to be from 4 to 5 days and the generation time from 19.2 to 24 hours. 3) At the inside of taste bud, labeled cells with relatively scanty number of silver grains were noticed in the basal part of the bud by 3 hours after the injection, and these cells tended to migrate toward the center of the bud later than 24 hours period. 4) There were observed, on the other hand, the presence of those cells that contained DNA labeled by ^3H-thymidine during its de novo synthesis and also those cells that were in the state of mitotic activity, the latter being less frequently.
