ESPE Abstracts

Background: Male genital abnormalities may be associated with environmental endocrine disruptors.

Objective and hypotheses: To observe the hypothalamic kiss-1 gene and the testis androgen acceptor (AR) gene expression level changes and the level of serum luteinizing hormone (LH), follicle stimulating hormone (FSH); testosterone (T) and Inhibin B (INH B) in neonatal rats which exposure to different doses of bisphenol-A (BPA). In order to explore the effects of neonatal exposure to different doses of BPA on the hypothalamic-pituitary-testis axis and the testis function in toddler and adolescent male rat.

Method: Neonatal male Sprague-Dawley (SD) rats were randomly divided into five groups: blank control, low-dose BPA (25 ug/kg per day), medium-dose BPA (50 ug/kg per day)) and high-dose BPA (250 ug/kg per day). The rats were subcutaneously injected with respective agents on postnatal days 1–7 (PND1-7). Pups were weaning on postnatal days 21 (PND21) and randomly sacrificed on postnatal days 22(PND 22) and postnatal days 50(PND 50)and collected blood.The hypothalamus and testis were taken and weighed. The hypothalamic Kiss-1 mRNA and the testis AR mRNA were measured by Real-Time PCR., The level of serum LH, FSH and T and INH B were measured.

Results: There was no significant difference between the control group and other five drug groups on the weight of rats. The medium- and high-dose BPA groups compared with the controls, the organ coefficient of testis decreased significantly in PND 50.In PND22 male pups, the medium and high dose BPA groups compared with the controls, the serum LH were decreased significantly The level of serum T obviously decreased in PND22 and PND 50.In high dose group of PND 22, the expression of hypothalamic Kiss-1 mRNA increased compared with the rest of the groups while in PND50, compared with control group,the medium and high dose groups Kiss-1 mRNA decreased. There were no significant difference in the mRNA expressions of testis AR with control group in PND 20 and PND 50.

Conclusion: Neonatal exposure to the low-dose BPA does not have a significantly influence on the hypothalamus–pituitary- testis axis and the testis function. Neonatal exposure to the medium- and high-dose BPA affect the expression level of the hypothalamic kiss-1 mRNA in toddler and adolescent male rat and may impair the function of testis and hypothalamus–pituitary-testis axis.