title: Biological activity and bioavailability of grain bound 14C-malathion residues in rats.
abstract: Paddy (unmilled rice), milled rice and maize-bound 14C residues were prepared using 14C-succinate-labelled malathion at 10 and 152 ppm. After 3 months, the bound residues accounted for 12%, 6.5% and 17.7% of the applied dose in paddy, milled rice and maize respectively in the grains treated at 10 ppm. The corresponding values for the 152 ppm were 16.6%, 8.5% and 18.8%. Rats fed milled rice - bound 14C-residues eliminated 61% of the 14C in the faeces and 28% in the urine. The corresponding percentages for paddy and maize were 72%, 9% and 53%, 41% respectively; indicating that bound residues from milled rice and maize were moderately bioavailable. When rice-bound malathion residues (0.65 ppm in feed) were administered to rats in a 5 week feeding study, no signs of toxicity were observed. Plasma and RBC cholinesterase activities were slightly inhibited: blood urea nitrogen was significantly elevated in the test animals. Other parameters examined showed no or marginal changes.
authors.affiliation: Department of Biochemistry and Microbiology, University of Agriculture, Serdang, Malaysia.
authors.forename: M A
authors.initials: MA
authors.lastname: Syed
authors.forename: J H
authors.initials: JH
authors.lastname: Arshad
authors.forename: S
authors.initials: S
authors.lastname: Mat
mesh_terms: D000818:Animals; D001682:Biological Availability; D001835:Body Weight / Q000187:drug effects; D002250:Carbon Radioisotopes; D002802:Cholinesterases / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005506:Food Contamination / Q000032:analysis; D008294:Malathion / Q000032:analysis / Q000493:pharmacokinetics*; D008297:Male; D012275:Oryza; D010573:Pesticide Residues / Q000032:analysis / Q000493:pharmacokinetics*; D051381:Rats; D011919:Rats, Inbred Strains; D003313:Zea mays
chemical_list: D002250:Carbon Radioisotopes; D010573:Pesticide Residues; D002802:Cholinesterases; D008294:Malathion