Studies on patients with polychlorinated biphenyl poisoning. 2. Determination of urinary coproporphyrin, uroporphyrin, delta-aminolevulinic acid and porphobilinogen.

Urinary excretion of heme precursors were evaluated in 69 human subjects who have consumed rice oil contaminated with polychlorinated biphenyls (PCBs). Twenty four hour urinary samples were collected from 20 normal healthy volunteers and 69 PCB poisoned human subjects and assayed for the concentrations of delta-aminolevulinic acid, prophobilinogen, uroporphyrin and coproporphyrin. PCB poisoning caused an increased excretion of delta-aminolevulinic acid (from 0.72 mg/24 hours to 1.00 mg/24 hours) and uroprophyrin (from 13.6 micrograms/24 hours to 41.2 micrograms/24 hours), but not the excretion of porphobilinogen (0.34 mg/24 hours) or coproporphyrin (30 micrograms/24 hours). The excretion pattern of urinary heme precursors associated with PCB poisoning is different from those due to lead or arsenic poisoning. The analysis of urinary heme precursors may be helpful for screening patients with PCB poisoning.