SYMPOSIA PAPER Published: 01 January 1991
STP23584S

Mechanism of Selective Toxicity of Diazinon to Killifish ( ) and Loach ( )

Source

This study was initiated to explain the acute toxicity difference (14 times in LC50) of killifish (Oryzias latipes) and loach (Misgurnus anguilicaudatus), two dominant fish species in Korean rice paddies, to diazinon, one of the widely used organophosphorus insecticides in Korea. Enzymatic activity of acetylcholinesterase (AchE) and microsomal fraction was used for the detection of inhibitory action of diazinon and Phase I metabolic activity of fish homogenate in vitro. Ethoxy-14C-labelled diazinon was used for tracing the absorption difference, as well as confirmation of the enzymatic assay result.

The results showed that: (1) inhibition of AchE by diazoxon in loach was 22-fold more potent than in killifish; (2) total radioactivity exposed to ethoxy-14C labeled diazinon was decreasing in killifish with daily analysis, while increasing in loach; (3) initial absorption ratio was 4.5:1 for killifish:loach; and (4) approximately 10 times more polar metabolites were formed in killifish within a 15-h period. It was concluded that the three factors, AchE inhibition, detoxification, and absorption were all significant for the selective toxicity of diazinon. Further study is under way to reveal the identity of the metabolites.

Author Information

Oh, HS
Toxicology Research Center, Korea Research Institute of Chemical Technology, Dae Jeon, Republic of Korea
Lee, SK
Toxicology Research Center, Korea Research Institute of Chemical Technology, Dae Jeon, Republic of Korea
Kim, Y-H
Toxicology Research Center, Korea Research Institute of Chemical Technology, Dae Jeon, Republic of Korea
Roh, JK
Toxicology Research Center, Korea Research Institute of Chemical Technology, Dae Jeon, Republic of Korea
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: E47
Pages: 343–353
DOI: 10.1520/STP23584S
ISBN-EB: 978-0-8031-5176-5
ISBN-13: 978-0-8031-1425-8