Correlation of mitochondrial ribonucleotide reductase and thymidine kinase activities with the synthesis of mitochondrial DNA in rat liver during regeneration

3H-thymidine incorporation into DNA of heavy mitochondria from regenerating rat liver and the change of mitochondrial thymidine kinase and ribonucleotide reductase activities are studied in vivo in regenerating rat liver within 6--48 hours after hepatectomy. Synthesis of mitochondrial DNA and changes in the activity of the enzymes studied are found to be undulate. Thymidine kinase activity maxima coincide with those of 3H-thymidine incorporation. Maximal activity of ribonucleotide reductase pre-exists maxima of mitochondrial DNA synthesis.