[Effects of maternal exposure to bisphenol A during pregnancy on puberty in advance and hypothalamo-pituitary gonadal axis hormones level in female offspring].

Objective: To investigate the effect of maternal exposure to bisphenol A on puberty in advance and hypothalamus-pituitary-gonad axis( HPG axis) hormones level in female offspring.

Methods: A total of 105 pregnant CD-1 mice aged 8 weeks were daily administered with BPA at four different doses( 0, 8, 40 and 200 mg/kg) by gavage from gestational day( GD) 0 to 18. Offspring were weighed and determined sex by anal reproductive distance after birth. From postnatal day( PND) 21-34, the vaginal opening of female offspring and distinguished the estrous stage through vaginal smears wereobserved. The level of GnRH, FSH, LH and E2 hormone in serum were detected.

Results: The mean initial time of vaginal opening in 8 mg/kg group [( 28. 0 ± 0. 36)days], 40 mg/kg group [( 28. 0 ± 0. 33) days] and 200 mg/kg group [( 28. 0 ± 0. 61)days]was earlier than that in the control group [( 30. 0 ± 0. 27) days]. The vaginal opening in advance rate of BPA exposure group was higher than that of the control group and the first estrus occurrence was earlier than controls( P < 0. 05). The levels of GnRH[8 mg/kg:( 9. 78 ± 1. 07) pg/mL, 40 mg/kg:( 11. 55 ± 1. 38) pg/mL, 200 mg/kg:( 10. 09 ± 1. 51) pg/mL]with increased expressions compared with the controls [( 5. 18± 4. 63) pg/mL]. LH level in low dose group [( 1. 86 ± 0. 79) pg/mL] was significantly lower than that in control group [( 2. 37 ± 1. 56) pg/mL]. The above differences were statistically significant( P < 0. 05).

Conclusion: These findings suggested that maternal exposure to BPA result in advancing puberty and increase the GnRH hormone level to affect the function of HPG axis in female offspring.