[DNA synthesis in the process of rat spermatogenesis]

The rat spermatogonia were fractionated in STA-PUT system within 24 hrs following 3H-thymidine injection. DNA isolated from the cells at certain stages of spermatogenesis (spermatogonia, leptotene-zygotene, pachytene, spermatids-spermatozoa) was studied by the method of reassociation kinetics and ultracentrofugation in CsCl gradient. A selective 3H-thymidine incorporation in the region of midrepetitious nucleotide sequences was found at all stages under study, except spermatids-spermatozoa. DNA synthesized during spermatogenesis forms in CsCl density gradient several "satellite" peaks in the "heavy" and "light" gradient zones.