740 



ADVENTURES IN RADIOISOTOPE RESEARCH 



Table 6. (Cont) 



of benzpyrene sarcomata investigated amounts to ten only; the 

 difference obtained in the renewal rate of the tvi^o types of sarcoma is 

 therefore to be interpreted cautiously. 



We investigated furthermore 5 retrograde benzpyrene sarcomata. Two 

 (163: 1 and 163: 2) are showing almost normal turnover rates, while 

 ^appreciably lower values were found for the remaining 3 sarcomata. 



Desoxyribosenucleic Acid Formation in Sarcomata of Colchicine 



Treated Rats 



In view of the effect of colchicine on the mitotic process, it was of 

 interest to investigate the effect of colchicine treatment on the turnover 

 of desoxyribosenucleic acid, and to determine if it is possible to obtain 

 similar effects by colchicine treatment as obtained by irradiation. The 

 following experiments were carried out: 



(a) Rats weighing 138 and 111 gm respectively were injected with 50 y 

 colchicine. Injection was repeated after a lapse of 6 days, and one day 

 later labelled sodiumphosphate was administered by subcutaneous 

 injection. The rat was killed, as in all our other experiments, 2 hours 

 later, and the desoxyribosenucleic acid of the sarcoma, weighing 23 gm, 

 and the inorganic P of sarcoma and plasma were isolated. 



(b) In these experiments 50 7 colchicin ewere injected subcutaneously, 

 one day before the administration of ^^p to rats weighing 112, 126, 165 

 and 125 gm respectively. 



(c) In this experiment 150 y colchicine were administered on three 

 consecutive days. One day later ^sp ^yas injected. 



(d) ^^P was administered 3 days after injecting 50 y colchicine. Weight 

 of rats was 120 and 155 gm resp. Weight of the only slightly necrotic 

 sarcoma was 9 and 7 gm respectively. 



