Nucleic acid and phospholipid synthesis in the regenerating liver of tumor-bearing mice.

The metabolic interrelationships between the growth of a rapidly proliferating tissue and of a transplanted tumor were investigated in the same animal. Liver regeneration and tumor growth were studied in C3H mice bearing a transplanted mam mary carcinoma. The rate of radioactive phosphorus incorporation in the DNA, RNA, and phospholipids of the liver and the tumor was deter mined at intervals of six hours after j>artial hepatectomy. The presence of the tumor did not affect significantly the time of onset, but increased markedly the rate of DNA synthesis in the regenerating liver from 24 to 36 hours after the partial hepatectomy. It had no effect on the liver phospholipid and RNA turnover rates. The tumor itself did not show any varia tion in the rate of MP incorporation in phospholipids and RNA throughout the 48-hour study period, but demonstrated an early fall and a subsequent rise in DNA synthesis.