Inhibition of δ-aminolevulinic acid dehydratase by trichloroethylene

Akio Koizumi, Hiroyoshi Fujita, Tetsuo Sadamoto, Masayuki Yamamoto, Miho Kumai, Masayuki Ikeda

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11 Citations (Scopus)


Male Wistar rats (8 animals/group; 180-200 g) were exposed continuously to trichloroethylene (TRI) for 48 or 240 h or methylchloroform (1,1,1-trichloroethane: MC for 48 h at 50, 400 and 800 ppm. The inhibition of δ-aminolevulinic acid dehydratase (ALA-D) was examined in liver, blood and bone marrow of naive and phenobarbital pretreated animals exposed to TRI. A clear cut dose-effect relationship between the exposure concentration or duration of exposure and the inhibition of ALA-D activity was seen for rats exposed to TRI. In addition to this finding, significant interaction between TRI exposure and phenobarbital treatment was observed in the inhibition of ALA-D in liver and blood. MC did not produce inhibition. Trichloroacetic acid and trichloroethanol failed to inhibit the ALA-D activity in vitro. It seems that a metabolite(s) of TRI other than the above 2 substances may play a role in the inhibition of ALA-D. The inhibition of ALA-D (38% or 48% of the control in liver or in blood, respectively) observed after the 240 h exposure at 400 ppm to TRI was accompanied by the significant elevation of δ-aminolevulinic acid synthase (186% of the control) in liver and the increase in excretion of δ-aminolevulinic acid in urine (142% of the control). This occurred without an apparent weight loss, liver injury or hematological changes.

Original languageEnglish
Pages (from-to)93-102
Number of pages10
Issue number2
Publication statusPublished - 1984 Mar


  • Phenobartal
  • Trichloroethylene
  • δ-Aminolevulinic acid
  • δ-Aminolevulinic acid dehydratase
  • δ-Aminolevulinic acid synthase

ASJC Scopus subject areas

  • Toxicology


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