Bergan A, Oström T, Enge I
Scand J Gastroenterol. 1977;12(5):605-9. doi: 10.3109/00365527709181341.
Between 10 and 20% of the bilirubin excreted in the bile is not derived from the breakdown of hemoglobin. When delta-aminolevulinic acid is given as a bilirubin precursor, 99% of the bilirubin formed is of this non-erythroid variety. The non-erythroid bilirubin has been supposed to be synthetized exclusively in the liver. Sequential samples of arterial, portal and liver vein blood, as well as of bile and thoracic duct lymph, were analyzed for bilirubin and non-bilirubin radioactivity following the injection of labeled delta-aminolevulinic acid in dogs. Radioactive bilirubin appeared in blood before it could be demonstrated in bile or lymph. The concentration differences between aortic, portal and liver vein blood displayed a considerable extrahepatic non-erythroid bilirubin synthesis. Most non-erythroid bilirubin synthetized in the liver is excreted directly into the biliary canaliculi.
胆汁中排泄的胆红素，有10%至20%并非来自血红蛋白的分解。当给予δ-氨基乙酰丙酸作为胆红素前体时，所形成的胆红素中有99%是这种非红细胞系来源的。过去认为非红细胞系胆红素仅在肝脏中合成。给狗注射标记的δ-氨基乙酰丙酸后，对动脉血、门静脉血、肝静脉血以及胆汁和胸导管淋巴的连续样本进行胆红素和非胆红素放射性分析。放射性胆红素在胆汁或淋巴中被检测到之前就已出现在血液中。主动脉血、门静脉血和肝静脉血之间的浓度差异显示出肝外存在相当数量的非红细胞系胆红素合成。在肝脏中合成的大多数非红细胞系胆红素会直接排入胆小管。
