EFFECT OF IRRADIATIOX ON HEMIX FORMATION 



631 



exposure to irradiation on the ^^Fe content of tlie plasma is seen from 

 Table 3. This table also contains data on the incorporation of ^^Fe into 

 hemoglobin, which is much more markedly depressed under the effect 

 of irradiation after the lapse of 48 hours than after that of 1 hour. 

 In these experiments 5 jug of iron as FeClg were interperitoneally injected 

 to each rabbit. Similar observations on the effect of irradiation on the 

 incorporation of ^^Fe into the red corpuscles were made by Hennessy 

 and HurF^^\ 



These results support the conclusion arrived at that for some time 

 after irradiation the completion of the hemoglobin content of the red 

 corpuscles is still going on in the marrow. 



b) Muscle myoglobin 



In view of the fact that the chemical composition of myoglobin closely 

 resembles that of hemoglobin — they are differing only as to their degree 

 of polymerisation — it was of great interest to investigate the effect 

 of exposure to irradiation on the incorporation of ^^Fe into the myo- 

 globin of guinea pigs extracted from their muscles. The method of puri- 

 fication was that described by Theorell and Akeson^^\ The myo- 

 globin obtained was practically free from hemoglobin as revealed by 

 a spectroscopic investigation of the CO-myoglobin. In 4 experiments 

 in each of which 10 female guinea-pigs having a weight of 450 — 550 gm 

 were injected 6 hours after exposure to 1400 r with 3 //gm of labelled 

 iron as sodium iron citrate and killed 18 hours later and 10 controls 

 were treated in the same way, the following rel. specific activity figures 

 were obtained for the myoglobin and hemoglobin iron of controls and 

 exposed animals. 



Under effect of exposure the ^^Fe incorporation into myoglobin was 

 thus reduced to 1/2, that into hemoglobin to 1/4 of that of the controls. 

 In the 2 last experiments we determined the effect of exposure on the 



Table 4. — Effect [or Irradiation on the Incorporation of ^^Fe 

 INTO Myoglobin and Hemoglobin of Guinea-pigs. Control = C, 



Exposed = R 



No. of expt. 



Rel. spec, activity* of 

 myoglobin 



^ . 

 Ratio T^— 

 R 



Eel. spec, activity of 

 hemoglobin 



„ . 



Ratio ^;r- 



R 



1 



2 

 3 

 4 



5.0 



4.6 

 3.6 



* Count per //gm Fe. 



