Exposure to Bisphenol a Alters the Hypothalamic-Pituitary-Thyroid Axis in Female Rats

FERNANDEZ MO; ROSA M; LUX LANTOS V; LIBERTUN C

Boston

Congreso; ENDO 2016; 2016

The Endocrine Society

AbstractBisphenol A (BPA) is a component of polycarbonate plastics, epoxy resins and polystyrene found in many common products. Several reports revealed potent in vivo and in vitro effects, as BPA acts like an estrogen agonist and/or antagonist and androgen and thyroid hormone antagonist. In this study we analyzed the effects of the exposure to BPA in the hypothalamic-pituitary-thyroid axis in female rats, both in vivo and in vitro.Female Sprague-Dawley rats were injected sc, daily from postnatal day 1 (PND1) to PND10 with BPA: 500 µg/50 µl oil (Hi), or 50 µg/50 µl oil (Me), or, in some cases, 5 µg/50 µl (Lo). Controls (Co) were injected with vehicle. TSH serum levels were determined (RIA) in PND13 females and in adult females in the morning of estrus. T3 and T4 (ELISA) serum levels were also determined in the adults. Primary pituitary cell cultures (PPC) were obtained from Hi, Me and Co adult females in estrus. Cells were cultured for four days in complete media and TSH was measured in serum-free media after 1 h of incubation. The in vitro model consisted of PPC obtained from PND13 normal females, preincubated for 24 h with BPA 1x10-7 M, E2 1x10-7 M or Control (C) and then stimulated with TRH 1x10-7 M. TSH was determined in the media after 1 h stimulation.Neonatal exposure to BPA did not modify TSH serum levels in PND13 females, but it did alter this parameter in adult females in estrus [TSH (ng/ml): Co=12.8±1.9, Lo=18.7±3.3, Me=28.1±4.3, Hi=23.4±3.7; Me vs Co p