Developmental toxicity of orally administered technical dimethoate in rats.
BACKGROUND
Dimethoate (O,O-dimethyl-S-(N-methylcarbamoyl-methyl) phosphorodithioate), an organophosphate insecticide, was examined for its potential to produce developmental toxicity in rats after oral administration.


METHODS
Pregnant Fischer 344 rats were given sublethal doses of 0 (corn oil), 7, 15, and 28 mg/kg/day dimethoate by gavage on gestation days (GD) 6-15. Maternal effects in 15 and 28 mg/kg/day dose groups included cholinergic signs such as tremors, diarrhea, weakness, and salivation, and depression in the maternal and fetal brain acetylcholinesterase (AChE) activities. Other maternal toxicity that included reduction in body weight and feed consumption was observed only in the treated group of 28 mg/kg/day. No maternal toxicity was apparent in the 7 mg/kg/day dose group.


RESULTS
Maternal exposure to dimethoate during organogenesis significantly affected the number of live fetuses, early resorption, and mean fetal weight in the 28 mg/kg/day dose group. No external, visceral, and skeletal abnormalities were observed in any of the treated groups compared to the control.


CONCLUSIONS
On the basis of the present results dimethoate can produce clinical signs of toxicity and significant inhibition of the maternal and fetal AChE activities in dose groups of 15 and 28 mg/kg/day and showed fetotoxicity without teratogenic effects at 28 mg/kg/day.
Department of Pesticide Chemistry and Toxicology, Faculty of Agriculture, Alexandria University, Alexandria, Egypt. aminafarag2002@yahoo.com
Amina T
AT
Farag
Tarek Abdel-Zaher
TA
Karkour
Ahmed
A
El Okazy
D000014:Abnormalities, Drug-Induced / Q000196:embryology*; D000110:Acetylcholinesterase / Q000378:metabolism; D000284:Administration, Oral; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004117:Dimethoate / Q000008:administration & dosage* / Q000633:toxicity*; D005247:Feeding Behavior / Q000187:drug effects; D005260:Female; D005333:Fetus / Q000002:abnormalities; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011247:Pregnancy; D051381:Rats; D011916:Rats, Inbred F344
D000110:Acetylcholinesterase; D004117:Dimethoate