628 



ADVEXTURES IX RADIOISOTOPE RESEARCH 



A different line of thought supports this view. Hemoglobin iron is 

 almost quantitatively reutihzecl for hemoglobin formation as shown by 

 Hahn et alS^"^\ We injected labelled red corpuscles of a donor rabbit to 

 an acceptor rabbit and after the short interval of only 5 hours found 

 90 times more ^sFe in the liver than in the spleen of the thoroughly per- 

 fused animals, the gall containing 2/3 of that of the last mentioned organ. 

 The reutilization of this iron for hemoglobin formation necessitates its 

 passage through the plasma to the marrow. Thus a continuous flow of 

 iron from the liver (and presumably other organs responsible for the 

 phagocytosis of red corpuscles) to plasma has to take place. In the 

 course of 120 days (the time necessary to replace the circulating human 

 red corpuscles) about 2 gm of iron has to pass from the depot organs to 

 the bone marrow. The corresponding figure in the rabbit in the course 

 of 50 days is about 0.1. 



Effect of irradiation on ^ape incorporation into hemoglobin 



As to be expected and also shown by Huff^^\ Hennessy^^^ and their 

 associates, irradiation strongly depresses the incorporation of ^sFe into 

 hemoglobin. Our results obtained with guinea-pigs injected within 6 

 hours after exposure and killed 17 hours later are seen in Table 2. 



In each of the experiments Nos. 9 to 16 the blood of 10 guinea-pigs, 

 in Nos. 21 and 22 of 20 animals was pooled. 



Incorporation of ^^Fe into hemoglobin was thus reduced by irradiation 

 in these experiments to 30% of that of controls. 



Table 2. — Effect of Irradiation 

 With 500 — 1300 r on the Incorpora- 

 tion OF ^^Fe into Hemoglobin 

 OF Gtjinea-pigs 



Mean value : 0.298 ± 0.158 



