抄録
DNA synthesis has been studied on the liver cells of mice in the restitution period after starvation. Tritiated thymidine (3H-TdR) was subcutaneously injected twice a day for ten days during the restitution period, in order to examine the incorporation of 3H-TdR into hepatic nuclei and the persistence of 3H-labelled nuclei in the liver.
After ten-day's labelling, about 40% of hepatic parenchymal cell nuclei was heavily labelled. More incidence of heavily labelled nuclei was observed at 1 week after the last injection of 3H-TdR. Thereafter, the percentage of heavily labelled nuclei remained nearly constant around 30%. If lightly labelled nuclei were taken into account, almost 80% of the parenchymal cell nuclei showed labelling of DNA. With exception at 1 week after the last dose of 3H-TdR, this total percentage of labelled nuclei remained unchanged about 60% for 6 weeks.
The incorporation of 3H-TdR into littoral cells of the liver was also observed. Throughout the present experimental period from 35 to 40% of littoral cells had labelled nuclei.
These results indiacte that DNA synthesis has occurred in the parenchymal and in the littoral cell nuclei during the restitution after starvation, and that the nuclei, which contain newly syntesized DNA, persist for a long period.
