title: Comparative evaluation on the biological monitoring of exposure to parathion and its methyl analog.
abstract: The effects of both parathion and methyl parathion on the inhibition of plasma cholinesterase were elaborated in a rat model employing a modified isocratic reverse-phase HPLC method coupled with UV detection for the determination of the urinary metabolite p-nitrophenol (U-4NP). A linearity of r2 > 0.995 was found for a standard curve ranging from 0.06 to 0.96 microg/mL with a % relative error of </= +/- 10% and a recovery of 89 +/- 2%. The % CV at all levels was </= 11%. A linear correlation was observed between the oral administration of parathion and methyl parathion for both the percent inhibiton of cholinesterase as well as the urinary elimination of 4NP. It is tentatively recommended that an U-4NP of 2. 0 mg/g creatinine be established as a biological exposure index (BEI) for methyl parathion.
authors.affiliation: Toxicology/Pharmacology Laboratory, Chang Gung College of Medicine and Technology, Tao-Yuan 333, Taiwan, Republic of China.
authors.forename: M J
authors.initials: MJ
authors.lastname: Chang
authors.forename: Y C
authors.initials: YC
authors.lastname: Chen
authors.forename: H J
authors.initials: HJ
authors.lastname: Yang
mesh_terms: D000818:Animals; D002800:Cholinesterase Inhibitors / Q000633:toxicity*; D002802:Cholinesterases / Q000097:blood / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D008297:Male; D008743:Methyl Parathion / Q000633:toxicity*; D010278:Parathion / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results
chemical_list: D002800:Cholinesterase Inhibitors; D008743:Methyl Parathion; D010278:Parathion; D002802:Cholinesterases