Urinary excretion of 5-hydroxyindoleacetic acid, delta-aminolevulinic acid and coproporphyrin isomers in rats and men exposed to lead.

The urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA), delta-aminolevulinic acid (ALA) and coproporphyrin (CP) isomers (I and III) was investigated in rats and workers exposed to lead. Urinary excretion of 5-HIAA, which is the major metabolite of serotonin, was not influenced by the lead exposure. However, a significant increase in urinary ALA and CP was found in rats and workers exposed to lead. In particular, the urinary excretion of CP-III was markedly increased compared to that of CP-I in rats and workers exposed to lead.