Studies on rat thyroid after oral administration of mancozeb: morphological and biochemical evaluations

Abstract

Mancozeb, an ethylenebisdithiocarbamate (EBDC), has been studied for its effects on rat thyroid. Single oral administration of mancozeb at different concentrations (9600, 12 000, 15 000 and 18 750 mg kg−1 body wt) has derived the oral LD50 value as 15 000 mg kg−1 body wt. in male rats. Mancozeb at repeated oral doses of 500, 1000 and 1500 mg kg−1 day−1 for periods of 30, 90, 180 and 360 days has produced dose‐dependent signs of toxicity and death of animals. The fungicide caused a significant increase in thyroid/body weight ratio and histopathological changes. Reduced levels of thyroid radioiodine (125I) uptake, serum protein‐bound iodine (PB125I), thyroxine (T4) and reduced activity of thyroid peroxidase (TPO) have also been observed after exposure to mancozeb. Thus, mancozeb has been shown to produce marked structural and functional changes in thyroid of rats.© 1997 John Wiley & Sons, Ltd. © 1997 by John Wiley & Sons, Ltd.

The effect of Maneb on implantation, fecundity rate and the thyroid activity in the rabbit

“…The effect of high doses of Maneb (2500 mg/kg), on the thyroid activity of rats was reported by previous investigations made by Worthing and Walker (1983). Besides, similar studies revealed that dithiocarbamates affects thyroid activity, by decreasing the secretion of TSH, causing a reduction in the circulating (T4) and inducing hypothyroïdy (Jeffrey et al, 2001 (WHO, 1988;Kachar et al, 1997). The results obtained in the present study suggest that the treatment with the Maneb especially with the doses 10 and 50 mg/kg for 10 days of pregnancy period in the rabbit caused a significant decrease in the number implantation.…”

Study on The Use of QuEChERS Method for Analysis of Organochlorine Pesticides Residues in Cow's Milk.

“…Increased thyroid weight has been found to be associated with hypertrophy and hyperplasia of the follicular cells of thyroid gland of rats after mancozeb treatment (Kacker et al, 1997B) .This findings might explain the increased relative weight of thyroid gland in the present study. Regarding serum biochemical parameters, glucose level, ALT and AST were decreased and total cholesterol was increased, while total protein and albumin were not changed (Table 4).…”

Effect of Subacute oral Mancozeb exposure and its detrimental impact on male reproductive health in Wistar rats

“…(1997) [18] reported similar increase in body weight after mancozeb exposure. One study showed no significant difference in weight gain in mancozeb treated animals when compared to controls.…”