[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.