Effect of ageing on rat liver regeneration after partial hepatectomy.

The effect of ageing on liver regeneration after two-thirds partial hepatectomy was evaluated using rats of 6 and 60 weeks of age. The induction of thymidylate synthase and thymidine kinase, which are rate-determining enzymes of DNA synthesis in liver regeneration, delayed by 24 h and the maximal activities were significantly lower in old rats. Effects of aging on liver weight and synthesis of DNA, RNA and protein were discussed quantitatively in terms of the relative restoration yield deduced from the comparison with the young animals.