The action of caffeine on X-irradiated HeLa cells. I. Delayed inhibition of DNA synthesis.
The action of caffeine on X-irradiated HeLa cells. I. Delayed inhibition of DNA synthesis.
复制标题
咖啡因对 X 射线照射的 HeLa 细胞的作用。
作者：
L. Tolmach;R. W. Jones;P. Busse
Treatment of HeLa S3 cells with 1 mM caffeine delays progression through G1 by 1.5 hours but causes no other detectable inhibition of cell progression; it sometimes results in a large stimulation of thymidine incorporation. When this concentration is applied to cells that have been irradiated with 1-krad doses of 220-kV X rays, there is a marked suppression of both the inhibition of DNA synthesis and G2 arrest induced by the radiation. Larger doses require higher concentrations of caffeine to suppress the inhibition of DNA synthesis. Delaying addition until the rate of synthesis is at its minimum (1.5 hours after irradiation with 1 krad) results in a slightly accelerated recovery of the rate. Treatment before or during irradiation is without effect on the inhibition. Removal of the caffeine as late as 6 hours after its addition at the time of irradiation results in a prompt inhibition in DNA synthesis that mimics that observed immediately after irradiation in the absence of caffeine. These findings raise ...
