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Comparative diazinon toxicity in guppy and zebra fish: Different role of oxidative metabolism
Author(s) -
Keizer Johannes,
D'Agostino Giuseppina,
Gramenzi Franco,
Vittozzi Luciano,
Nagel Roland
Publication year - 1993
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620120713
Subject(s) - diazinon , guppy , metabolite , toxicity , toxicology , biology , pesticide , fish <actinopterygii> , chemistry , ecology , fishery , biochemistry , organic chemistry
Guppies pretreated with 1.1 μmol/L diazinon (0.5 times the LC50 with the guppy) for 7 d were less susceptible to the toxicity of the compound. The LC50 in these fish was about five times higher than that in nonpretreated animals. The lethal body burden and the slope of the concentration‐response curve of diazinon in pretreated guppies were similar to those in zebra fish. The 7‐d pretreatment of zebra fish with 12 μmol/L diazinon (0.5 times the LC50 with the zebra fish) did not affect the susceptibility of this species to diazinon. The pretreatment of guppies resulted in a strong inhibition of the formation of diazoxon and pyrimidinol during incubations of diazinon with the hepatic postmitochondrial supernatant. During exposure of guppies and zebra fish to diazinon, the tissue concentration of the metabolite, pyrimidinol, initially increased and then declined to very low levels. In the guppy, concurrently with the decrease of the metabolite concentration, the parent compound began accumulating again after a temporary steady state. The hypotheses of this paper are that the toxicity of diazinon in the guppy is due to its metabolism to a highly toxic metabolite, likely diazoxon; and in zebra fish or pretreated guppies having low rates of diazinon metabolism toxicity is due to the accumulation of the parent compound.