CONICET | Buscador de Institutos y Recursos Humanos

Bisphenol A (BPA), an endocrine disruptor, is a component of epoxy and polyestirene resins used in food packaging and dentistry. In vitro it has shown weak estrogenic actions, 10.000-fold less potent than estradiol (E2), but it has pronounced in vivo effects as inducing irregular estrous cycles and cystic follicles in neonatally BPA-treated Sprague-Dawley (SD) rats. First, we determined the in vitro effects of BPA on the pituitary response to GnRH (G). In primary pituitary cultures (PPC) from 13-day-old female SD rats, after 24 hours of BPA 1.10-7M or E2 1.10-7M preincubation, an increase in basal FSH release was observed with regards to controls [FSH (ng/ml): Control=0.81±0.05; BPA=1.49±0.22; E2=1.71±0.19, p<0.05], while only E2 enhanced G-induced FSH release [G=3.39±0.01 vs. E2+G=4.15±0.32, p<0.05]; neither BPA nor E2 modified basal or G-stimulated LH release. To further study a possible effect on LH, and on PRL, two new experimental models were used. The effects of chronic in vivo treatment with BPA on basal and stimulated LH and PRL release was determined in PPC, in addition to studying in vivo LH release after G administration. Females were treated daily, from postnatal days 1 to 10, with BPA dissolved in oil (500 mg/day, sc.) or vehicle and studied at postnatal day 13. In vivo pretreatment with BPA diminished LH release in PPC, but did not modify the response to G; an increase in basal PRL was determined (p<0.05). In vivo, rats pretreated with BPA had lower absolute serum LH levels, both basally and after G stimulation, than controls (p<0.05), although the G-induced percent of LH increase was similar. We conclude that BPA has marked effects on pituitary secretion, modifying hormone release both after in vitro and in vivo treatments. (CONICET, ANPCYT, UBA).