THYMIDINE AS A SYNCHRONIZING AGENT .2. PARTIAL RECOVERY OF HELA CELLS FROM UNBALANCED GROWTH

Randomly growing cultures of HeLa‐S3 cells were subjected to synchronizing treatment with excess thymidine. Unbalanced growth occurred during the thymidine treatment, but the abnormal cellular composition was found to revert to control levels so that at the time of the first mitosis following a 12–24 hour treatment with the inhibitor the cellular DNA, RNA and protein content and cell size were close to control values. However, an alkaline deoxyribonuclease which attacks denatured DNA was still found to be significantly elevated at this time. The results argue against the use of thymidine as a synchrony producing agent. Copyright © 1969 Wiley‐Liss, Inc.