Bilirubin diglucuronide as the main source for in vitro formation of delta bilirubin

✍ Scribed by Yukihiko Adachi; Akira Kambe; Masaki Yamashita; Toshio Yamamoto

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 426 KB
• Volume: 5
• Category: Article
• ISSN: 0887-8013
• DOI: 10.1002/jcla.1860050507

✦ Synopsis

To clarify which of the bilirubin moieties is increased with time. A similar amount of delta responsible for the formation of bilirubin bonded to albumin (delta bilirubin) in icteric serum, the in vitro formation of delta bilirubin from bile acid-free bilirubin glucuronides and unconjugated bilirubin was examined by highperformance liquid chromatography. Bovine serum albumin (150 pmol/liter) was mixed with equimolar bilirubin diglucuronide (BDG), bilirubin monoglucuronide (BMG), or unconjugated bilirubin (UCB) and incubated in the dark at 37°C under argon gas saturation. Although no delta bilirubin was formed immediately, formation eventually occurred and bilirubin was formed when human serum albumin was used instead of bovine serum albumin. Of the three types of bilirubin, BDG was found to be the greatest source of delta bilirubin, whereas UCB produced the least. On the other hand, photoirradiation of a mixture of bovine serum albumin and UCB at a molar ratio of 1:l resulted 6 hr later in the formation of three times as much delta bilirubin as in nonirradiated specimens. This photoinduced delta bilirubin formation increased further when the UCWalbumin molar ratio was increased to 2:l.