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

Quantitation of ineffective erythropoiesis from the incorporation of [15N] delta-aminolaevulinic acid and [15N] glycine into early labelled bilirubin. I. Normal subjects

The incorporation of [15N] glycine into early labelled bilirubin and haemoglobin haem was measured in four haematologically normal subjects, using the clearance of [14C] bilirubin to measure total bilirubin production rate. Hepatic haem turnover was calculated from the incorporation of [15N]=sigma-aminolaevulinic acid into early labelled bilirubin. From the exprimental data previously published data in normal subjects a method is derived for the quantitation of ineffective erythropoiesis which can be applied to similar studies in patients with haematological disorders.

Quantitative studies of the delivery of hepatic-synthesized bilirubin to plasma utilizing -aminolevulinic acid-4- 14 C and bilirubin- 3 H in man

After the simultaneous intravenous administration of unconjugated bilirubin-(3)H and delta-aminolevulinic acid-4-(14)C, the plasma disappearance curves of unconjugated bilirubin-(3)H and the plasma appearance curves of biosynthesized unconjugated bilirubin-(14)C have been defined in seven patients, three of whom had acute intermittent porphyria (AIP). The incorporation of (14)C into plasma unconjugated bilirubin, derived by an analysis which involves deconvolution of the two plasma curves, varied between 13.1 and 23.5% (mean 19.3%) of the injected dose in the nonporphyric patients and between 5.4 and 13.6% (mean 8.3%) of the injected dose in the porphyric patients. In five of the patients, the stercobilin-(14)C specific activity in a pooled specimen of feces was measured, enabling the following further values to be calculated: (a) the total (14)C radioactivity incorporated into bilirubin (21.0 and 25.3% [mean 23.2%] of the injected dose in two of the nonporphyric patients and between 8.5 and 25.3% [mean 14.2%] of the injected dose in the porphyric patients), and (b) the proportion of hepatic synthesized bilirubin delivered directly to plasma in the unconjugated form (between 0.520 and 0.904; mean for nonporphyric patients 0.712; mean for porphyric patients 0.614). The results demonstrate that a large proportion of bilirubin derived from hepatic hemes passes through the plasma in the unconjugated form before conjugation and secretion into bile.