206 



E. Hammarsten 



the isotope contents in guanine and adenine from the poly- 

 nucleotides and the isotope contents in glycine from the 

 proteins (Fig. 1). Certainly the previously mentioned 

 direct incorporation of glycine into both the purines and the 

 proteins plays an important role in this correlation. 



In spite of the wide deviations from a mean value we think 

 that this correlation is not accidental but indicates a general 

 tendency to simultaneous metabolic activity of polynucleo- 



10 



Glycine/ 



/Adenine 



Glycine/ 



/Guanine 



10 



20 



30 



Fig. 1. Relation of isotope contents in glycine from proteins 

 (abscissa) and in guanine and adenine from PNA-polynucleo- 

 tides (ordinate) in bone marrow and liver from hen. The values 

 are calculated on the basis of 100 per cent in administered 



glycine. 



tides and proteins. This connection might possibly signify 

 a functional interaction of polynucleotide and protein turn- 

 over, and should be considered along \vith the turnover rates 

 found in the experiments on regenerating rat liver (Figs. 2, 

 3 and 4). 



These experiments show that the maximum turnover rates 

 for all nitrogenous compounds in PNA in cell nuclei and cyto- 

 plasm and in DNA appeared at about 30 hours after partial 

 hepatectomy. The greatest increase in the amount of PNA 



