Whole-body metabolism of the organophosphorus pesticide, fenthion, in goldfish, Carassius auratus

Comp Biochem Physiol C Toxicol Pharmacol. 2000 Jul;126(3):259-66. doi: 10.1016/s0742-8413(00)00124-9.


The in vivo metabolism of fenthion, an organophosphorus pesticide, and its sulfoxide (fenthion sulfoxide) was examined in goldfish (Carassius auratus). When goldfish were administered fenthion i.p. at a dose of 100 mg/kg, two metabolites were isolated from the tank water. They were identified as fenthion sulfoxide and fenthion oxon, in which > P = S of fenthion is transformed to > P = O, by comparing their mass and UV spectra, and their behavior in HPLC and TLC, with those of authentic standards. However, fenthion sulfone was not detected as a metabolite. The amounts of fenthion, fenthion sulfoxide and fenthion oxon excreted within 4 days were 2.7, 3.4 and 2.5%, of the initial dose of fenthion, respectively. Unchanged fenthion was detected in the body of the fish to the extent of 42-50% of the dose after 10 days, but fenthion sulfoxide and fenthion oxon showed very low concentrations. When fenthion sulfoxide was administered to the fish, about 70% of the dose was excreted unchanged into the tank water within 24 h, but little of the reduced compound, fenthion, was found. In contrast, fenthion was detected at 2.1% of dose in the body of goldfish as a metabolite of fenthion sulfoxide. The fact that fenthion is metabolized to the toxic oxon form in fish presumably has environmental and health implication for its use as a pesticide.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Fenthion / metabolism*
  • Fenthion / toxicity
  • Goldfish / metabolism*
  • Insecticides / metabolism*
  • Insecticides / toxicity
  • Sulfoxides / metabolism


  • Insecticides
  • Sulfoxides
  • Fenthion