Effect of the remaining ischemic liver lobes on DNA synthesis in rat liver regeneration following 70% functional hepatectomy.

After 24 h of 70% partial hepatectomy (PH), the activities of thymidylate synthase (TS: EC 2.1.1.45) and thymidine kinase (TK: EC 2.7.1.21) increased by 4.0 and 9.3 times, respectively, compared with their normal levels taken just after PH. In the ligation experiment, where the left lateral and median lobes were ligated as usual PH but were left without resection, regeneration occurs in the non-ligated lobes whose TS and TK levels after 24 h of the ligation were significantly suppressed compared with the PH group. The DNA content of the non-ligated lobes was also lower than that of PH group.