METABOLISM OF HEMATIN 575 



gration of the erythrocyte does it combine with serum albumin to 

 form methemalbumin. 



2.3. Metabolism of Hematin 



While hematin is considered by Duesberg (639), Bingold {265,267, 

 269) and Fairley as an abnormal breakdown product of hemoglobin, 

 and by Duesberg and Bingold as a blind alley of hemoglobin metab- 

 olism, some other workers believe that it is a normal intermediate in 

 bile pigment formation. 



Brugsch {370-372) claimed that the excretion of bilirubin in bile 

 fistula dogs was increased by intravenous injections of hematin, and 

 although neither Duesberg {639), Fairley {733,735), or Watson and 

 co-workers could find increased bilirubin formation under these con- 

 ditions,* Brugsch's claim has recently been confirmed by Benard, 

 Gajdos, and co-workers {211). Gitter and Heilmeyer {1007) found 

 the urobilinogen excretion to be increased after hematin injection in 

 only one case out of many, but Watson and co-workers {2113,2990) 

 found this effect in humans and concluded that hematin is quanti- 

 tatively converted to bile pigment. 



As will be shown below, direct observation of the fate of the hema- 

 tin does not support the view that it is rapidly metabolized. Although 

 many factors may be involved in producing increased urobilinogen 

 excretion (c/. Chapter XI) the balance of the evidence quoted above 

 seems to indicate a real increase of bilirubin excretion after hematin 

 injection. It does not follow, however, that this is due to metabolism 

 of hematin. Brugsch .{370) found increases in bilirubin excretion in 

 bile fistula dogs after urobilin injection, when, as has been shown in 

 Chapter XI, there is absolutely no evidence that the transformation 

 of urobilin to bilirubin can be brought about in the body. The 

 increase of bile pigment excretion is therefore probably caused indi- 

 rectly, the excretion of bilirubin in the bile being variable and 

 depending on other factors {cf. With, 3111-3113). 



Lemberg {1688) injected solutions of mesohematin into rabbits. 



This caused bilirubinuria and urobilinuria, but the effect was not 



due to increased bile pigment formation from mesohematin. The 



bile did not contain bile pigments with saturated side chains, but 



only bilirubin and biliverdin; this was established by the position of 



* Watson and co-workers {2113) claim an occasional increase of serum bilirubin 

 after injection of hematin in humans; the presence of unaltered hematin in the serum 

 may, however, cause the findings of erroneously high bilirubin values with the 

 Jendrassik method which was used for the estimation. 



