Determination of porphyrins in bile using high performance liquid chromatography and some clinical applications.

A simple and fast HPLC method for the determination of porphyrins in bile without extraction is described. Porphyrins were determined in bile from control subjects and from patients after orthotopic liver transplantation, including three patients with erythropoietic protoporphyria. It was found that: 1) coproporphyrin I is the predominant porphyrin in bile of controls, accompanied by some coproporphyrin III and protoporphyrin, whereas protoporphyrin mostly but not always is the predominant porphyrin in the bile of erythropoietic protoporphyria patients. In two of the three erythropoietic protoporphyria patients, the bile contained a hundred times more protoporphyrin than that of non-porphyric orthotopic liver transplantation patients. The third erythropoietic protoporphyria patient remained cholestatic and was unable to excrete sufficient amounts of protoporphyrin. 2) All investigated bile samples contained no secondary porphyrins derived from protoporphyrin, i.e. no deutero-, pempto-, or mesoporphyrin. Even when extracts of bile and serum were concentrated fifty to a hundred times, no traces of deutero-, pempto- and mesoporphyrin were detected. This complete absence of secondary porphyrins suggests that an enterohepatic circulation of dicarboxylic porphyrins from the distal gastrointestinal tract does not exist. 3) The HPLC chromatograms contain peaks from unknown compounds. No correlation between porphyrins and these compounds was found. Porphyrin profiles were followed in the bile of some orthotopic liver transplantation patients. Three episodes are recognizable. During the first three days after orthotopic liver transplantation there is a very high coproporphyrin excretion. There is then a lag of one to three weeks, in which no or very low porphyrin concentrations are detectable, followed by the restoration of normal biliary porphyrin patterns.

Hereditary tyrosinaemia type I: a long-term study of the relationship between the urinary excretions of succinylacetone and delta-aminolevulinic acid.

Patients with hereditary tyrosinaemia type I (HT) excrete large amounts of succinylacetone (SA) in urine. Owing to structural resemblance of SA to delta-aminolevulinic acid (ALA), SA inhibits the second enzyme in the pathway for haeme biosynthesis, porphobilinogen synthase, resulting in increased urinary ALA excretion. We investigated the relationship between urinary SA and ALA excretions of two patients with different forms of HT (late-infantile and juvenile). In both patients the urinary SA and ALA excretions showed a more or less inverse correlation. The patient with the early-infantile form of HT had a relatively greater increase in urinary SA and ALA excretions in comparison to the patient with the juvenile form of HT. A possible explanation for this unexpected inverse correlation between the urinary excretion of SA and ALA might be a lack of intramitochondrial glycine, a substrate for delta-aminolevulinic acid synthesis. It has been reported previously that high concentrations of SA reversibly and competitively inhibit the transport of glycine through membranes.