Studies on the Mechanism of Bile Pigment Formation in Vivo. II. On the Process of Intrahepatical Production of Bilirubin.

1. When hemolysed blood is administered orally to rabbits, in cases of healthy and those with blocked reticulo-endothelial systems, a transient increase in the verdohemoglobin (M. Engel) is seen in circulating blood, while in that of rabbits with impaired parenchymal liver cells, no such increase occurs. 2. On irrigation of hemolysed blood through rabbit livers, in healthy rabbits production of indirect bilirubin may be demonstrated while in that with blockage of the reticulo-endothelial system or with impaired liver parenchymal cells, this may not be seen. Moreover, in this case of blockade of the reticulo-endothelial system. production of verdohemoglobin may be demonstrated. while none whatsoever may be demonstrated in cases of impaired liver parenchmal. On the other hand on irrigation of verdohemoglobin and biliverdin solutions, in healthy and in impaired liver parenchymal cell cases, production of bilirubin may be observed while absolutely none was detected in cases of blocked reticulo-endothelial systems, 3. Concluding from the results stated above and those of clinical experiments stated elsewhere, the following process is assumed: when blood is imposed on the organism it is primarily phagocytosed by the reticulo-endothelial system, next dissolved to verdohemoglobin {M. Engel) in the parenchymal cells of the liver, and then dissolved into globin, iron, and biliverdin in the reticulo-endothelial system, of which biliverdin is further reduced to bilirubin. A portion of this remains in the circulating blood as indirect bilirubin, while the majority of it is esterized in the parenchymal cells of the liver, and proceeds to the bile ducts as direct bilirubin.