640 



ADVENTURES IX RADIOISOTOPE RESEARCH 



THE CAPACITY OF PLASMA PROTEINS FOR COMBINING WITH IRON 



The interpretation of the manifold cHnical experience that a part of 

 the injected iron disappears very rapidly, as observed earlier by 

 Waldenstrom and others, was made considerably easier by the dis- 

 covery by HoLMBERG and Laurell^^^ that the physiological iron of the 

 plasma is attached to a protein fraction in the transferrin. In recent 



Gosamt — Eiweip — 6,35 gm % 



Albumin 

 oc, 



r 



41,9 % 

 9,3 " 

 13,5 " 

 14-,2 n 

 21,1 ■ 

 1 00,0 % 



Mlb. 



Fig. 1. Localization of the binding of radioactive iron to the /?j 



globuhn of plasma. 

 Gesamt-Eiweiss = total protein. Albumin = albumen. 



years it has been possible to confirm this result by electrophoretic 

 investigations. For instance, it is evident in Fig. 1, which is taken from 

 the paper of Jasinski and Wuhrmann.^^b) that all the labelled plasma 

 iron detected autoradiographically is situated in the same position as 

 the i^i globulin fraction. The main portion of the transferrin of the /S^ 

 globulin is present in the IV : 7 fraction of the plasma. 



If more ferrous sulphate is added to the plasma than can be bound 

 by the amount of transferrin present, then the excess reacts, in contrast 

 to the iron in transferrin, with dipyridyl. The transferrin of the plasma 

 in a healthy person can combine with about 315 /^gm % of iron. 



Laurell^^^ ascertained the combining capacity of the plasma for iron, 

 both in physiological and pathological conditions in numerous cases, 

 in his comprehensive studies in which he also established the diagnostic 

 importance of this quantity. A plasma iron content of 150 figm % may, 

 however, be taken as normal. This applies when it is postulated that 

 the combining capacity of plasma for iron amounts to about SOO^agm %. 

 When the combining capacity for iron is decreased owing to the abnormal 

 synthesis of protein, as in pernicious anaemia, a plasma iron content 



