794 



ADVENTURES IN RADIOISOTOPE RESEARCH 



Table A. — Incorporation of Carbon-14 in the Tissues of 



Rai'idly Growing Rats Following the Administration of 



Labelled Acetate (Dose 950 r.) 



Organ 



Arbitrary 

 activity figures 



Per cent increase in 



carbon-14 incorporation 



due to irradiation 



Kidnej's Control 



Irradiated 

 Intestinal mucosa Control 



Irradiated 

 Liver Control 



IiTadiated 

 Muscles Control 



Irradiated 



22.05 

 25.74 

 12.83 

 16.93 

 11.20 

 12.70 

 22.05 

 25.74 



16.8 

 31.8 

 13.5 



16.7 



Table B. — Incorporation of Carbon-14 with the Tissues of 



Full-grown Mice 



Organ 



Arbitrary 

 activity figures 



Per cent increase in 



carbon-14 incorporation 



due to irradiation 



* In contrast to all other organs investigated in two subsequent experiments, carl)on-14 uptake by 

 muscle tissue was not found to be influenced by irradiation. 



four hours they observed an exhalation of 87 per cent of the carbon-14 

 administered. Since our experiments lasted about eight hours, and rapidly 

 growing rats and mice were used, we can expect a still larger percentage 

 exhalation to have taken place. In view of the small percentage of carbon- 

 14 incorporated with the tissues, a decrease of 1 per cent only in the 

 amount exhaled carbon-14 during the experiments can be expected 

 to lead to an increase of 10 per cent, or possibly much more, in the carbon- 

 14 uptake by the tissues. If this interpretation is correct, it should be 

 possible by measuring the increase in the incorporation of carbon-14 

 in the animal tissue following irradiation or other metabolic interferen- 

 ces to determine small changes produced in the metabolic rate. 



References 



l.G. Hevesy, Nature, Lond. 163, 869 (1949). 



2. R. G. Gould, F. M. Sinex, I. N. Rosenberg, A. K. Solomon and A.B, 

 Hastings, J. Biol. Chem. 177, 295 (1949). 



