title: Binding of 14C-furazolidone metabolites to the muscular and hepatic proteins of trout.
abstract: A high level of 14C was found to bind irreversibly with the liver proteins of rainbow trout (Oncorhyncus mykiss) exposed to 135 mg/kg bodyweight of 14C-labelled furazolidone (14C-FZ) in fish feed daily for 10 days. After the cessation of 14C-FZ treatment, hepatic protein-bound 14C in trout stayed high for at least 30 days. The chemical identity of protein-bound 14C remained to be elucidated. However, a part of the protein-bound 14C in the liver and muscle could be released as 3-amino-2-oxazolidinone by acid hydrolysis. The formation of protein-bound 14C in the liver was investigated further with trout dosed intravenously with different 14C-FZ doses at 10 degrees C or with 5 mg/kg FZ at different water temperatures. 14C binding to the liver proteins was found to increase with increasing FZ dose or water temperature. Results of these studies indicate that protein-bound 14C in the muscle and liver of trout is related to the formation of reactive intermediates from FZ. However, additional studies on the identities of the protein-bound FZ residues are required before they can serve as useful biomarkers to monitor FZ exposure in farm fish.
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Colombia, Canada.
authors.forename: F C
authors.initials: FC
authors.lastname: Law
authors.forename: J
authors.initials: J
authors.lastname: Meng
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000378:metabolism* / Q000493:pharmacokinetics; D001667:Binding, Competitive; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D004350:Drug Residues / Q000378:metabolism* / Q000493:pharmacokinetics; D005506:Food Contamination; D005664:Furazolidone / Q000008:administration & dosage / Q000378:metabolism* / Q000493:pharmacokinetics; D006868:Hydrolysis; D007275:Injections, Intravenous / Q000662:veterinary; D007553:Isotope Labeling; D008099:Liver / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D011485:Protein Binding; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000890:Anti-Infective Agents; D002250:Carbon Radioisotopes; D005664:Furazolidone