992 



ADVENTUEES IN EADIOISOTOPE KESEAECH 



cytes, and also by the low inorganic phosphate content of the corpuscles, 

 and finall y by the fairly slow rate of penetration of phosphate from the 

 plasma in to the corpuscles, and vice versa. 



Red cor puscles can also he labelled by introducing radio-iron, ^spe or 

 59Fe. Iron-labelled red corpuscles keep their label throughout their life. 

 As, however, the labelling of erythrocytes with radio-iron can only be 

 carried out in vivo it necessitates having blood donors to whom iron 

 of appreciable radioactivity must be administered. Iron-labelled red 

 corpuscles are not applied in the determination of the erythrocyte content 

 of the human circulation. Such corpuscles proved to be useful, inter al., 

 in the study of the post-transfusion survival of erythrocytes preserved 

 during several weeks. 



APPLICATION OF i^C IN THE STUDY OF METABOLIC DEPRESSORS 



AND ACCELERATORS 



Although the rapid change in the sensitivity of the indicator during 

 the experiment may be disturbing, as in the study of the mineral consti- 

 tuents of the skeleton (see p. 982), it is most advantageous when we 

 are interested in restricting the formation of labelled components to a 

 .short time interval. This is the case, as we saw, in the study of the life- 



2000 



Liver 

 Control 

 DinitrocyclopenTylphencI 



Fig. 14. — Effect of dinitrocyclopentylphenol on the incorporation 

 of i*Cinto total fats and total tissue of mice liver. Groups of animals 

 killed at different times after injection of CH3 • J^CO^Na (reproduced, 

 with permission, from Arch, internal. Pharm. Therap., 86, 33 (1951). 



