Urinary excretion of biopyrrin in unconjugated hyperbilirubinemia

We determined the urinary excretion of biopyrrin, an oxidative metabolite of bilirubin, in three jaundiced subjects with unconjugated hyperbilirubinemia and in eight normal controls. We used an enzyme-linked immunosorbent assay (ELISA) and an anti-bilirubin monoclonal antibody, 24G7 (Shino-Test Corporation, Kanagawa, Japan). The biopyrrin excretions, expressed as the ratio in urine of biopyrrin to creatinine, were measured in random urine specimens from jaundiced adults and were compared to the same in random urine specimens from normal adults. The central 95% of the distribution range, defined by us as the reference range for the urinary biopyrrin/creatinine excretion, was 0.5 -3.3 mol/g in presumably healthy adults. The biopyrrin/creatinine excretions from the jaundiced adults were significantly higher than the reference range (p<0.05). We found that for the 24-hr biopyrrin excretion from normal subjects, and that the central 95% of the data was 0.9 -1.5 mol/day; the amounts in the jaundiced adults were significantly higher than the reference range (p<0.05). Our observations suggest that there is an enhanced bilirubin catabolism to biopyrrin in subjects with unconjugated hyperbilirubinemia. Bilirubin, Jaundice, Gilbert syndrome, Random and 24-hr urine, Biopyrrin, Hyperbilirubinemi