Changes in the Hypothalamic-Pituitary-Gonadal Axis in Adult Male Rats Poisoned with Proteus and Biscaya Insecticides

Insecticides may have negative effects on reproductive organs. Given the interaction between leptin and the hypothalamic-pituitary-gonadal (HPG) axis, we sought to investigate the changes in leptin and the HPG axis in adult male rats poisoned with Proteus and Biscaya insecticides.

Our experimental subjects were 110 adult male Wistar rats (80-90 days of age; average weight=200-210 g). They were randomly split into 11 groups of 10 rats: control, sham, and 9 experimental groups namely treatment with 2.75, 5.5, and 11 mg/kg/BW of Proteus, treatment with 1.5, 3, and 6 mg/kg/BW of Biscaya, treatment with 2.75 mg/kg/BW of Proteus+1.5 mg/kg/BW of Biscaya, treatment with 5.5 mg/kg/BW of Proteus+3 mg/kg/BW of Biscaya, and treatment with 11 mg/kg/BW of Proteus+6 mg/kg/BW of Biscaya. Intraperitoneal injections were performed over a 14-day period. For bloodletting at the end of the experiment, blood samples were withdrawn from the rats in order to investigate the serum concentration of luteinizing hormone (LH), follicle-stimulating hormone (FSH), gonadotropin- releasing hormone (GnRH), testosterone, and leptin. The data were analyzed using SPSS, version 16, via ANOVA and the Duncan test. A P value equal to or less than 0.05 was considered statistically significant.

Our comparisons between the experimental groups (average and maximum compound concentrations of Proteus and Biscaya) and the control group showed a significant decrease in the mean serum levels of FSH (P=0.001), LH (P=0.001), GnRH (P=0.001), testosterone (P=0.005), and leptin (P=0.001) in all the experimental groups in a dose-dependent manner.

Proteus and Biscaya decreased GnRH, LH, FSH, and testosterone by reducing the serum level of leptin in the hypothalamus in a dose-dependent manner.