Dimethoate is an organophosphate pesticide.1 It is acaricidal against Kanzawa spider mites (LC50 = 7 ppm in an aqueous suspension) and inhibits purified Kanzawa spider mite acetylcholinesterase (AChE; IC50 = 3.3-5.2 nM). Dimethoate (50-200 μM) reduces motility and viability and induces abnormal morphology of rat sperm.2 It also increases production of malondialdehyde (MDA) and reduces superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (Gpx) activities in rat epididymal sperm. In vivo, dimethoate (28 mg/kg per day) decreases sperm count, motility, and viability and increases the percentage of morphologically abnormal sperm in rats.3 Dimethoate also induces formation of carcinomas in the adrenal, thyroid, and pituitary glands of male and female rats as well as testicular atrophy, chronic renal disease, polyarteritis, and parathyroid hyperplasia in male rats.4
1.Kuwahara, M.Insensitivity of the acetylcholinesterase from the organophosphate-resistant Kanzawa spider mite, Tetranychus kanzawa Kishida (Acarina: Tetranychidae) to organophosphorus and carbamate insecticidesAppl. Ent. Zool.17(4)486-493(1982) 2.Ben Abdallah, F., Fetoui, H., Zribi, N., et al.Antioxidant supplementations in vitro improve rat sperm parameters and enhance antioxidant enzyme activities against dimethoate-induced sperm damagesAndrologia44(Suppl 1)272-279(2012) 3.Abdallah, F.B., Slima, A.B., Dammak, I., et al.Comparative effects of dimethoate and deltamethrin on reproductive system in male miceAndrologia42(3)182-186(2010) 4.Reuber, M.D.Carcinogenicity of dimethoateEnviron. Res.34(2)193-211(1984)