Originally published in the Proceedings of the Fifth Congress of Haematology 



p. 10 (1955). 



64. viPPLICATION OF ISOTOPIC INDICATORS 

 IN HAEMATOLOGY 



G. Hevesy 



Paper read at the Fifth Congress of Haematology 



IsoTOPic indicators have a widespread application in haematology. 

 Their use has broadened our knowledge of the origin and metabolism 

 of the plasma proteins, of the path of porphyrin synthesis and the syn- 

 thesis of globin and haemin; this application has permitted determination 

 of the life-time of various structural components of the blood, and has 

 facilitated determination of the plasma volume and the amount of 

 circulating red corpuscles, to name only a few regions of application. 

 In this paper we shall be concerned with the application of radio-iron 

 as an indicator in the study of the metabolism of plasma iron. 



THE IRON CONTENT OF BLOOD PLASMA 



The diagnostic importance of ascertaining the iron content of blood 

 plasma, the existence of which had already been demonstrated by the 

 experiments of Fontes and Thivolle^i^ Barkan^^)^ Henriques and 

 RocHE^^\ Warburg^^^ and Warburg and Krebs^^^ was early emphasized 

 by Heilmeyer and Plotner^^^ The analytical method worked out by 

 these authors has facilitated the clinical performance of these determin- 

 ations to a very considerable extent. 



After intravenous injection of iron salts, whose iron content, as empha- 

 sized earlier by Heilmeyer, should not exceed about 10 mgm, since 

 the ions of iron exert a toxic action, a very rapid migration of part of 

 the injected iron takes place out of the blood fluid while the other, 

 larger, part is responsible for a somewhat more lasting increase of the 

 plasma-iron content. The iron content of the blood fluid, which amounts 

 to about 127 figm % in a healthy person, rises after injection of 10 mgm of 

 iron as ferrous chloride to 389 mgm %, but after only 2 hr its value falls 

 to 349 mgm %.<^^ After oral addition of 0.55 gm of iron in the form of ferrous 

 tartrate the iron content of the plasma rises to almost twice the normal 

 value but, after 1 day has elapsed, the normal level of iron is again 

 estabhshed^^V We shall return later to these observations. 



