Dimethoate effects on thyroid function in suckling rats.
The aim of our work is to study dimethoate effects on thyroid function given in drinking water (40 mg/kg body weight, equivalent to 0.2 g/L) to mothers from day zero until the 10th day after delivery. Pups and their mothers were sacrificed on day ten after parturition. Compared to a control group, dimethoate-treated pups showed a 48% decrease in body weight which could be attributed to a defect in thyroid hormones. Indeed, after treatment by dimethoate, plasma rates of free T4 and T3 decreased by 56% and 40% in the young and by 27% and 15% in dams respectively. We can attribute the reduction in plasma thyroxine and triiodothyronine rates to a decrease in thyroid iodine levels (-75%) in the young and (-24%) in their mothers. The decrease in production of thyroid hormones after dimethoate treatment affect thyroid stimulating hormone (TSH) levels. In fact, plasma TSH levels were multiplied in dimethoate-treated group by factors of 2.31 in dams and 1.96 in their offspring. These biochemical modifications confirmed the histological thyroid aspects of pups and dams. In fact, in dimethoate-treated rats, some thyroid follicles of pups presented vesicular cavities without colloid; others contained colloid. However in dams, thyroid follicles presented cubical epithelial cells which surrounded empty vesicular cavities.
Mahjoubi-Samet
A
A
Animal Physiology Laboratory, Life Sciences department, Sciences Faculty of Sfax, Route de la Soukra Km 3.5. BP 802. 3018 Sfax-Tunisie.
Hamadi
F
F
Soussia
L
L
Fadhel
G
G
Zeghal
N
N
D000818:Animals; D000833:Animals, Suckling; D001835:Body Weight; D004117:Dimethoate / Q000008:administration & dosage / Q000633:toxicity*; D005260:Female; D005269:Femur / Q000254:growth & development / Q000473:pathology; D007306:Insecticides / Q000008:administration & dosage / Q000633:toxicity*; D007455:Iodine / Q000032:analysis; D008431:Maternal-Fetal Exchange; D009929:Organ Size; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013959:Thyroid Diseases / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology; D013961:Thyroid Gland / Q000737:chemistry / Q000254:growth & development / Q000503:physiopathology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D007306:Insecticides; D014284:Triiodothyronine; D013972:Thyrotropin; D007455:Iodine; D013974:Thyroxine; D004117:Dimethoate