Effects of Cypermethrin on Sexual Behaviour and Plasma Concentrations of Pituitary-Gonadal Hormones

Abstract

Background Pyrethroids are commonly used as insecticides for both household and agricultural applications, and have recently been linked to endocrine disruption. Cypermethrin is a type П pyrethroid which is used widely throughout the world. The present study was aimed to investigate the effects of cypermethrin on the sexual behaviour and plasma level of pituitary-gonadal hormones of adult male mice. Materials and methods Research methodology comprised injecting mice daily with cypermethrin (10, 15, 20 mg/kg i.p.) or DMSO (0.2 ml) for five weeks. Receptive female mice were used to test male sexual behaviors (sniffing, following, mounting, and coupling). Plasma concentrations of testosterone, luteinizing hormone (LH) and follicle stimulation hormone (FSH) were measured after five weeks treatment using the ELISA method. Results The results of the present study showed that cypermethrin-treated groups exhibited reduced sexual behavior when compared with the control group. Assay results demonstrate significantly reduced serum testosterone levels (p<0.05) versus the control group, whereas FSH and LH values increased significantly. Conclusion This study demonstrates that cypermethrin reduces plasma testosterone concentrations and thus is able to disrupt sexual behaviours.

Keywords

• cypermethrin
• pituatory-gonadal axis
• sexual behaviour
• endocrine disruptors