Originally published in Acta Cheni. Scand. 9, 509 (1956). 



62. EFFECT OF IRRADIATION ON HEMIN FORMATION 



R. BoNNicHSEisr and G. Hevesy 



From the Nobel Institute for Biochemistry and Institute of Organic Chemistry 

 and Biochemistry, University of Stockholm, Sweden 



Irradiation with Roentgen rays was found to depress very appreciably the rate 

 of extrusion of ^sFe bound to /^^-globulin in the circulation of the rabbit, the depres- 

 sion being much more pronounced 2 days after irradiation than shortly after 

 exposure. It is suggested that erythrocytes of the bone marrow which have not 

 yet completed their hemoglobin content are radioresistant and continue to incor- 

 porate s'Fe in the bone marrow of the irradiated animal. Correspondingly, the 

 effect of exposure to radiation on the rate of extrusion of ^^Fe from the plasma 

 gets strongly pronounced only after the lapse of several hours. 



A radiation dose which reduces the incorporation of ^^Fe into the hemoglobin 

 to 30% of that of controls does not diminish the rate of incorporation of ^^Fe 

 into cytochrom b of the liver of guinea-pigs. 



The study of iron metabolism can be approached in different wayS' 

 a very profitable one being the study of the fate of plasma iron. Iron 

 utilized for hemoglobin formation has to pass the plasma, so iron coming 

 from and going to the various organs in which it is present as a consti- 

 tuent of ferritin, hemosiderin, myoglobin, cytochrom, catalase or other 

 compounds. 



Flexner et alS^ injecting labelled ferric chloride into the circulation 

 of guinea-pigs observed a rapid initial disappearance of the radioactive 

 iron from the circulation followed by a slower process. They interpreted 

 the first process to be due to the disappearance of inorganic iron, the 

 second to iron bound to proteins. These early experiments thus brought 

 out already the difference between the circulating "physiological" 

 iron and the plasma foreign iron injected into the circulation. The phy- 

 siological plasma iron is bound to the /^j-globuline of the plasma which 

 amounts to 3%, of the plasma proteins. This protein fraction, the trans- 

 ferrin, is identical with Cohn's fraction IV— 7 as shown by Holmberg 

 andLAURELL*^9\ by Laurell'^^) and others. That the albumine fraction 

 of the plasma proteins does not fix iron, was recently demonstrated by 

 WuHRMANN and Jasinski*^*-* by combining paper chromatographic with 

 radioactive measurements. From the spots of the paper diagram of 

 the plasma proteins from a rabbit 10 minutes previously injected with 



