Stimulation of polyamine synthesis in relation to nucleic acids in regenerating rat liver

Abstract

The effect of partial hepatectomy on the liver polyamines and nucleic acids was studied in the rat. Partial hepatectomy causes an early stimulation of spermidine synthesis, as indicated by the marked increase in the incorporation of [ 14C]methionine into this polyamine, as early as 4–8 h after operation. At 16 h the specific activity of spermidine was about 10-fold that of the sham-operated controls. The total spermidine content of the liver was already significantly elevated at 16 h, and at 64 h it was 3.6-fold that of the controls. The specific activity of spermine, on the other hand, did not increase until 16–20 h and the total amount of spermine per liver not until 64 h post-operatively. The total amount of liver ribonucleic acid was significantly increased at 32 h and that of deoxyribonucleic acid at 64 h. The ratio polyamine nitrogen to RNA phosphate remained quite constant during liver regeneration. The present observations are discussed on the basis of the hypothesis that tissue polyamines may be essential as physiological stabilizers of nucleic acids, especially RNA.