Effects of haem infusion on biliary secretion of porphyrins, haem and bilirubin in man

Abstract. Employing a continuous bile collection, we measured the bile secretion of porphyrins, haem (iron protoporphyrin IX regardless of oxidation state) and bilirubin in five healthy subjects. The baseline values for the flow of porphyrins in the bile were: 4·7 pL 1·9 nmol/h uroporphyrin, 27·3 pL 3·8 nmol/h coproporphyrin and 39·2 pL 11·7 nmol/h protoporphyrin. Bile haem flow was 59·7 pL 12·6 nmol/h, and that of bilirubin 23·8 pL 8·2 μmol/h. Following haem injection (6·4 μmol/kg) the flow of protoporphyrin but not of the other porphyrins was reduced, and the bile haem flow increased (232 pL 109·5 nmol/h), while the flow of bilirubin did not increase significantly. A few patients with representative porphyrias showed the expected increase in copro‐ and protoporphyrin in the bile. The patient with coproporphyria exhibited a bile flow of coproporphyrin of 1470 pL 133 nmol/h and of protoporphyrin of 334 pL 29 nmol/h; haem infusion significantly reduced the bile flow of both porphyrins (to 649 pL 101 for copro‐ and 215 pL 36 nmol/h for protoporphyrin). The patient with protoporphyria had an increased protoporphyrin flow, yet haem infusion caused no reduction in protoporphyrin flow (106 pL 7 after v. 81·4 pL 13 nmol/h before haem). In conclusion, we found that haem and porphyrins are normal constituents of bile, and that injected haem appears in bile. Bile bilirubin did not rise within 12 h after haem infusion a finding which warrants further investigation.