210 



E. Hammarsten 



stomach tube a diet containing amino-acids as nitrogen 

 source. The feeding began four hours after the operation 

 and an adequate amount was given in portions six times per 

 24 hours. Fig. 7 shows that the PNA synthesis starts earher 

 when the hver is forced into activity and that the protein 

 synthesis lags somewhat behind, as in the earher experiments. 

 Some very important experiments by A. L. Schade and 

 co-workers on B. jjroteus have shown that growth may be 



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'I PNA Guanine 



TCA Protein 







20 40 60 80 



Time in hours 



Fig. 7. Isotope contents at different stages of regeneration in 



rat liver. 



inhibited by cobalt without any influence on the synthesis of 

 PNA. This experiment emphasizes in a convincing way the 

 secondary place of protein synthesis to that of PXA synthesis 

 in the total picture. 



From all this one would expect that an inhibition of nucleic 

 acid synthesis and turnover would decidedly inhibit protein 

 synthesis. Whether the experiments on the purine isomers 

 (for example those by Hitchings and others) have anything 



