[Corticosterone, a synchronizing factor for liver cells]

The clone Fu 5 a of the Reuber Hepatoma cell line was incubated with corticosterone for 48 hours. The incorporation of labelled thymidine into DNA was inhibited to 10%. After this time corticosterone was removed from the medium. The DNA-synthesis increased for ten hours, the maximum was sixteen times higher than in the controls. The conclusion drawn was that corticosterone is able to block liver cells in a part of G1 phase of the cell cycle, so that the cells become synchronous.