Disturbances of Haemoglobin Synthesis in Lead Poisoning 



that the greater part of the protoporphyrin is in the cytoplasm ; the 

 nuclei contain only one third of it, while the reticulum seems to 

 contain no porphyrin. We are thus inclined to think that it is especially 

 in the erythroblast that protoporphyrin is formed, and that the 

 synthesis of haemoglobin probably takes place in the cytoplasm of 

 the erythroblast. In fact, a similar analysis made by means of radio- 

 active iron again showed that the greatest quantity of iron in the 

 cell is to be found in the cytoplasm. Histochemical analysis of the 

 bone marrow permitted us to observe that lead does not appear in 

 the erythroblast. 



20 000 



Figure 2 



Therefore we may conclude that in lead poisoning the metal has a 

 direct action, either on the erythroblast, or more probably on the 

 transport system of iron from the reticuloendothelial system to the 

 erythroblast ; in this way it inhibits the synthesis of the haemoglobin 

 and provokes the formation of protoporphyrin. We were never able 

 to observe the presence of important quantities of protoporphyrin in 

 the other organs, even in the liver or the musculature. 



These observations made us wonder whether lead could inhibit not 

 only the synthesis of haemoglobin but also that of the other haems, 

 particularly the cellular ones. In the course of experiments on lead 

 poisoning of the rabbit, our collaborator A. Prader 9 followed the 

 activity of non-haemoglobin iron, of haemoglobin, and of cytochrome 

 C which is a cellular haemin closely resembling haemoglobin in 

 chemical structure (protoporphyrin + iron + protein). The researches 

 of Prader can be summarised in Table I. 



Thus we must conclude that in lead poisoning, although we can 

 regularly observe a considerable decrease of haemoglobin, the cyto- 

 chrome C is not decreased, but on the other hand invariably increases. 

 Indeed we can observe a change in the effect on the cytochrome 



255 



