The incorporation of delta aminolaevulinic acid and glycine into faecal stercobilin and coproporphyrin in man.

Abstract

Summary:The incorporation of [4‐14C]ALA and [2‐14C]glycine into haem, faecal coproporphyrin and stercobilin was studied in patients with various disorders. After the administration of [4‐14C]ALA, the specific activities of isolated faecal copropor‐phyrin and stercobilin increased and declined quickly within 3–4 days. These changes were associated with each other, and this relationship suggests that they arise from a common source. Incorporation of the labelled precursor into haem was minimal. When [2‐14C]glycine was the precursor, the rise and fall of faecal Coproporphyrin activity was independent of that of stercobilin and the stercobilin activity maintained a plateau for several days after the fall of faecal Coproporphyrin activity. This was associated with incorporation of the precursor into red cell haem. The activity peak in stercobilin which appeared at the end of red cell life span was not associated with faecal Coproporphyrin activity. These findings are consistent with the presence of two components of early‐labelled bilirubin. The first of these is associated with faecal Coproporphyrin activity and independent of erythropoiesis and the second is unassociated with faecal Coproporphyrin and closely related to erythropoiesis.Faecal Coproporphyrin activity was not related to red cell destruction, but correlated with hepatic production of bilirubin, and is thought to be hepatic in origin.