Evaluation of the effects of α-cypermethrin on fetal rat testicular steroidogenesis.

Pregnant Sprague-Dawley rats were administered the insecticide α-cypermethrin at doses of 0.1, 1, 5, or 10mg/kg/day, or di-isobutyl phthalate (DIBP) at 250mg/kg/day, by gavage, from gestation day (GD) 13 to 19. Testicular testosterone production and the expression of several key genes related to cholesterol and androgen synthesis and transport were assessed in GD 19 male fetuses. Dams treated with 10mg/kg/day of α-cypermethrin showed clinical signs of neurotoxicity and reduced body weight gain. α-Cypermethrin had no significant effect on post-implantation loss, fetal weight, incidence of male fetuses per litter, or anogenital distance of the male fetuses. In the fetal testes, mRNA expressions of HMG-CoA synthase and reductase, SRB1, StAR, P450scc, 3βHSD, P450 17A1, and 17βHSD were not affected by exposure to α-cypermethrin. Testosterone production by the fetal testis was significantly reduced at 5 and 10mg/kg/day of α-cypermethrin, although to a much smaller extent than in DIBP-exposed fetuses.