Assessment of Liver Function Before and After Liver Transplantation

Abstract

Bilirubin is the end product of heme catabolism and has no physiological function, yet it has been the subject of intense investigation, with millions of dollars being spent yearly by clinicians and scientists [1]. From its structure (Fig.la), one would predict that it was very water-soluble; however, at pH 7.4 its solubility is in the nanogram range. Chemists explain this occurrence as a result of bilirubin forming a “ridge tile” through the diacid state with six intramolecular hydrogen bonds [2, 3]. This renders bilirubin insoluble (Fig.lb). Thus bilirubin is not secreted in urine, but is converted to conjugates within the liver. These appear in bile, mainly as bilirubin diglucuronide with minor components of bilirubin monoglucuronide and a diester containing monoglucuronide and monoglucoside [4, 5].