Cell Division Kinetics and Dna Synthesis in the Immature Sertoli Cells of the Rat Testis

Summary. Using [3H]thymidine and autoradiography, the kinetics of cell division were studied in the immature Sertoli cells of the newborn rat testis. The average durations of the cell cycle and its components were: generation time, 16·4 hr; DNA synthesis, 10·1 hr; mitosis, 0·75 hr; G2 plus prophase, 3·6 hr. It was also shown that the mitotic activity of the immature Sertoli cells continues until 2 weeks after birth, whereas a decreasing percentage of these cells continues to incorporate [3H]thymidine until the 7th postnatal week. Mitotic and labelling patterns determined at various stages in the maturation of the Sertoli cells were correlated with events in the seminiferous epithelium.