THE FORMATION OF BILE PIGMENT FROM HEMOGLOBIN

Abstract

Previous investigation had proved that bile pigment is formed in the spleen and bone marrow. Since bilirubin is made from hemoglobin it seemed desirable to determine whether the injection of hemoglobin would increase the bilirubin production in these 2 known areas of bilirubin formation. The injection of laked blood into the blood entering the spleen gave rise to definite increases in the bilirubin of the blood leaving the spleen by the splenic vein. This increase was usually noticed within 15 minutes after injection and continued for about 2 hours. Various control experiments gave no such increases. The injection of laked blood into the blood entering the bone marrow (tibia) was likewise followed by increases in the bilirubin of the blood coming from the bone. The injection of laked blood into the blood supply to muscle alone gave no increase in the bilirubin content of the blood returning from the muscle. The injection of hemoglobin into the general circulation increased the bile pigment content of the blood and this increase was more marked in the blood coming from the spleen and bone marrow. The bilirubin content of the blood was determined by the spectrophotometric method. In addition to the finding of an increased bilirubin content of the blood following hemoglobin injections, another substance appeared in the blood during the period of greatest bilirubin formation. This substance has a characteristic spectral absorption band at 630 to 640[mu][mu] and it may be identified as hematin. The appearance of hematin during the active formation of bilirubin from hemoglobin would indicate that the process of disintegration of hemoglobin into hematin and globin occurs more rapidly than the formation of bilirubin from hematin. Thus the presence of hematin in the blood in disease might easily be interpreted as evidence of increased destruction of hemoglobin. This finding would apparently be of considerable importance in the study of hemolytic icterus and also of value in differentiating the various types of anemia.