Originally published in Kgl. Danske Vidensk. Selskab Biol. Medd. 17, 



No. 8 (1942). 



71. THE EFFECT OF X-RAYS ON THE RATE 

 OF NUCLEIC ACID FORMATION IN JENSEN- SARCOMA 



H. EuLER and G. Hevesy 



The Vitamin Institute of the University of Stockholm and the University 

 of Theoretical Physics, University of Copenhagen 



The detection of the effect of X-rays on sarcomas is usually studied in 

 the following way. Fragments of the irradiated sarcoma are transferred 

 by inoculating normal animals and tests are made to find out whether 

 or not the sarcoma has grown after a few days. We have tried to replace 

 this procedure by a chemical test. There are numerous experiences which 

 support the statement that doses which are effective against sarcoma 

 do not substantially affect the metabolic processes taking place in the 

 tissue cells, and that are the processes taking place in the cell nucleus 

 which primarily succumb to the action of the radiation. In the search 

 for a chemical test for the effect of X-rays on the sarcoma it was there- 

 fore evident that the processes occurring in the cell nucleus should be 

 studied in more detail. The nucleic acids are among the most important 

 constituents of the cell nucleus. 



Nucleic acid plays an essential part in cell division. Kossel, for 

 example, has shown that the changes occurring in the course of sperma- 

 togenesis consist in degradation and synthesis of proteins and in the 

 synthesis of the histonamine or protamine nucleate, which is compara- 

 tively poor in protein and Caspersson's^^^ studies of the absorption of 

 ultra-violet radiation by dormant and dividing cell nuclei have made 

 it apparent that Kossel's scheme of protein synthesis is valid also for 

 the ordinary mitotic cell, division. 



The mitotic division of cells is retarded by comparatively small doses 

 of X-rays and, on the basis of the above discussion, it might be expected 

 that the irradiation of tissue with X-rays would cause a diminution in 

 the of rate of formation of desoxyribo nucleic acid in the cell nucleus. 

 This view has induced us to study the formation of desoxyribo nucleic 

 acid in the Jensen-sarcoma of the rat, before and after irradiation 

 with X-rays. 



^T. Caspersson, Chromosoma 1, 562 (1940). 



