AUTORADIOGRAPHIC STUDY OF DNA SYNTHESIS AND THE CELL CYCLE IN SPERMATOGONIA AND SPERMATOCYTES OF MOUSE TESTIS USING TRITIATED THYMIDINE

摘要: Mice were injected intraperitoneally with 15 µc of H3-thymidine. The time course the labeling in spermatogonia and spermatocytes was studied by using autoradiography on 5 µ sections stained periodic acid-Schiff method hematoxylin over a period 57 hours after injection. Four generations type A (called AI, AII, AIII, AIV), one intermediate, B occur cycle seminiferous epithelium. average life span is about same all spermatogonia, i.e., 27 to 30.5 hours. pre-DNA synthetic time, including mitotic stages from metaphase through telophase portion interphase preceding DNA synthesis, also not very different, ranging between 7.5 10.5 remarkable difference exists, however, duration synthesis post-DNA period. long highly variable (14.5 hours), little shorter less intermediate (12.5 hours) AIV (13 much constant AIII (8 AII AI (7 spermatogonia. Conversely, corresponding essentially prophase, short (4.5 longer (6 more (11 (14 premeiotic takes place primary during resting phase terminates just before visible onset meiotic prophase. Its 14 No further later spermatogenesis.