bilirubin-diglucuronide and Cholestasis

Topics: Animals; Bile Pigments; Bilirubin; Chemical Phenomena; Chemistry; Cholestasis; Crigler-Najjar Syndrome; Female; Fishes; Gilbert Disease; Glucuronosyltransferase; Humans; Hyperbilirubinemia; Intestinal Absorption; Intestine, Small; Kidney; Liver; Male; Microsomes, Liver; Models, Biological; Pregnancy; Rats; Rats, Gunn; Rats, Inbred Strains; Saimiri; Urobilinogen

Bilirubin conjugates in the serum of cholestatic pediatric patients were investigated with Micronex high-performance liquid chromatography. Serum bilirubin was resolved into four fractions: delta bilirubin (Bd), bilirubin diglucuronide (BDG), bilirubin monoglucuronide (BMG), and unconjugated bilirubin (Bu). The conjugated bilirubin (BDG+BMG) fraction in preoperative patients with biliary atresia (BA) was 48.8 +/- 5.1%, which was significantly higher than that in patients with infantile hepatitis (P < .01). Among postoperative BA patients who recovered from jaundice, the Bd fraction increased during the first month, remained elevated (60% to 80%) for a while, and then gradually decreased. After 6 months, the Bd fraction decreased to 30% in the jaundice-free survivors, but was still higher than that in controls (7%). Even after the total serum bilirubin had normalized (< or = 1.0 mg/dL), distribution of bilirubin fractions remained abnormal, possibly reflecting impaired hepatic excretion of bilirubin. In conclusion, measurement of the conjugated bilirubin fraction enabled BA to be differentiated from infantile hepatitis, and the delta bilirubin fraction proved to be an important indicator of cholestasis in postoperative BA patients with normal serum bilirubin.

Topics: Biliary Atresia; Bilirubin; Child, Preschool; Cholestasis; Chromatography, High Pressure Liquid; Diagnosis, Differential; Hepatitis; Humans; Infant, Newborn; Jaundice, Neonatal; Postoperative Complications

Azopigments were obtained from the delta fraction of bilirubin (mammalian biliprotein) in cholestatic sera of men, rats and guinea pigs by diazo reaction with diazotized p-iodoaniline and analysed by t.l.c. Delta bilirubin of men and rats generated both unconjugated and glucuronide-conjugated azodipyrroles, whereas that of guinea pigs, in which the predominant form of conjugated bilirubin in serum was bilirubin monoglucuronide, generated only unconjugated azodipyrrole. We further analysed the azopigments by reversed-phase h.p.l.c. to distinguish their endovinyl and exovinyl isomers. The results indicated (a) that covalent binding of bilirubin to protein occurs exclusively on the conjugated dipyrrolic (either endovinyl or exovinyl) half of the parent conjugated bilirubin, (b) that both bilirubin monoglucuronide and bilirubin diglucuronide generate delta bilirubin, the latter yielding a 'conjugated' form of delta bilirubin that preserves the glucuronic acid moiety on the dipyrrolic half not bound covalently to protein, and (c) that therefore at least four forms of delta bilirubin exist in jaundiced sera of men and rats.

Topics: Aniline Compounds; Animals; Bilirubin; Cholestasis; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Diazonium Compounds; Guinea Pigs; Humans; Protein Binding; Pyrroles; Rats; Rats, Inbred Strains; Tetrapyrroles