Bile, bilirubin conjugates

Most assays are based on the transformation of bilirubin conjugates into azo derivatives (Section 4.3). In evaluating such methods, chromatographic analysis of the azo derivatives is a useful supplement to the study of color yields. A review on the diazo-coupling of bile pigments in various biological media, and on the separation and structure elucidation of the... 

As yet only a limited number of bilirubin conjugates can be synthesized in vitro. Mono- and diglucuronosides of bilirubin predominate in rat bile (F6, Hll, 03, S6). In accordance with these observations, isolated liver preparations and liver slices from rat (S6), and rat hepatoma cells (R9)... 

K3. Kuenzle, C. C., Bilirubin conjugates of human bile. The excretion of bilirubin as the acyl glycosides of aldobiouronic acid, pseudoaldobiouronic acid and hex-uronosylhexuronic acid, with a branched-chain hexuronic acid as one of the components of the hexuronosylhexuronide. Biochem. J. 119, 411-435 (1970). 

VI. Van Damme, B., Fevery, J., and Heirwegh, K. P. M., Altered composition of bilirubin conjugates in rat bile after obstruction of the common bile duct. Ex-perientia 26, 27-38 (1971). 

In liver, bilirubin undergoes enzymic conjugation and is secreted in bile in the form of water-soluble derivatives. A large body of literature279 exists on the separation and identification of bilirubin conjugates appearing in normal and pathologic bile, icteric sera, and urine. 

Bilirubin is highly water-insoluble and therefore its elimination from the circulation requires its chemical conversion in the liver to water-soluble conjugates that are normally excreted into the bile. Bilirubin circulates in plasma tightly bound to albumin, and is taken up into the liver by a carrier-mediated process whose competitive inhibition... 

In Crigler-Najjar syndrome type /activity of hepatic bilirubin UDP-glucuronyltransferase is undetectable and bilirubin conjugates are absent from the serum, bile, and urine, but biliary secretion of sulfobromophthalein and indocyanine green is normal. The disease is apparent shortly after birth, kemicterus develops, and death commonly occurs during the neonatal period. The effectiveness of phototherapy is often transient. The enzyme is not inducible by phenobarbital. This autosomal recessive defect occurs in all races. The Gunn strain of Wister rats has a similar genetic defect and has been used to study the syndrome. 

In the terminal ileum and colon the bilirubin conjugates arc attacked by bacteria to fomi a group of compounds which are known collectively as stercohiliiioaeii, most of which arc excreted in faeces. Some are absorbed and eventually re-excreted from the bixly by way of bile. Small amounts of these tctrapyrroles are found in urine in which they are known as urohilinof en. 

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