792 



ADVENTURES IN RADIOISOTOPE RESEARCH 



Ratio of Caiibon-14 Content of 1 mgm of Ptteine Isolated from Desoxyribo- 

 NTJCLEic Acid of Non-irradiated and Irradiated Rats Six Hottrs after Ad- 

 ministration OF ABOTTT 0.4 MGM OF LABELLED CaRBON AS AcETATE TO EACH OF 



91 One- to Three-Week-old Rats 



Organ 



Ratio of "C content o£ purine 

 from desoxyribonucleic acid iso- 

 lated from non-irradiated and 

 irradiated rats, respectively 



I Ratio of "C content of 

 1 mgm protein from 

 organs of non-irradiated 

 rats, respectively 



Group 

 2 3 



Group 

 3 



Intestinal mucosa 



Liver 



Muscles 



Kidneys 



Non-irradiated 

 Irradiated . . . . 



3.7 X 10-5_2.4 X 10-4 

 1.7 X 10-5—1.3 X 10-4 



4.1 X 10-*- 



5.2 X 10-4- 



-6.3 X 10-4 

 -7.8 X 10-4 



0.90 

 0.50 

 1.0 

 1.0 



Percentage of administered ^^C incorporated in 1 mgm intestinal mucosa: 



Purine Protein 



min. max. min. max. 



last-mentioned compound in the irradiated animal. The observation 

 that the rate of formation of a main constituent of cell nuclei is reduced 

 appreciably after irradiation, helps to explain the blocking effect of 

 irradiation on cell division and the formation of anomalous mitotic 

 products in the irradiated tissue. 



References 



1. A survey of earlier work has been given by G. Hevesy, Bev. Mod. Phys. 17^ 

 102 (1945). See also H. B. Jones, personal communication (1946), J. S. Mitchell 

 and B. E. Holmes, Ann. Rep. British Empire Cancer Campaign 9, 136 (1947); 

 B. E. Holmes, Brit. J. Radiol. 20, 450 (1947). 



2. W. C. Schneider, J. Biol. Chem. 161, 293 (1945), 



