Nucleic Acid and Polyamine Synthesis in the Rat during Short-term Protein Deficiency: Responsiveness of the Bone Marrow and Liver to Blood Loss

Abstract

The effect of blood loss on nucleic acid and polyamine synthesis in bone marrow and liver was studied in protein-deficient rats. Bone marrow, in comparison with the liver, is a tissue normally characterized by a relatively low rate of RNA synthesis, but a high rate of DNA synthesis. Twenty-eight-day-old rats were fed diets containing either 3.5 or 26% protein for 4 days before removal of an estimated 25% of their blood volume. After this, they were continued on their dietary regimens. H-thymidine was used as a precursor of DNA; and activities of thymidine kinase, uridine kinase and ornithine decarboxylase were used to estimate DNA, RNA, and polyamine synthesis, respectively. In protein-deficient animals, bone marrow DNA synthesis was stimulated in a normal manner after blood loss. However, the enzymes of RNA and polyamine synthesis were not increased. Conversely, in the liver, the activities of uridine kinase and ornithine decarboxylase were stimulated by blood loss, whereas DNA synthesis was inhibited. J. Nutr. 104: 59-64, 1974.