Neonatal exposure to Bisphenol A alters steroids hormones and GnRH-I content in the ovary of adult rats

BOURGUIGNON N; BONAVENTURA MM; LUX LANTOS V; LIBERTUN C

Houston

Congreso; ENDO 2012; 2012

The Endocrine Society

Bisphenol A (BPA), is an endocrine disruptor with multiple effects; it behaves as an estrogen agonist and/or antagonist and as an androgen antagonist. In previous works we described the effects of BPA on the hypothalamic-pituitary-gonadal axis in female rats; we found that neonatal exposure to BPA was associated in adulthood with high serum estradiol (E2) and testosterone (T) levels, reduced serum progesterone (P), and altered in vitro hypothalamic GnRH secretion. Animals exposed to BPA also had altered ovarian morphology (1, 2, 3). Following this line, here we study the ovarian content of E2, P4, T and GnRH-I. Female Sprague-Dawley rats were injected subcutaneously, daily from the day of birth to postnatal day (PND) 10 with BPA in castor oil at 50 ìg/50ìl (BPA50), 500 ìg/50ìl (BPA500), or castor oil (Control) (1). Rats were sacrificed in the morning of estrus at 110-120 days of age. The ovarian content of E2, P, T and GnRH-I were evaluated by RIA. Results were expressed as means SE. Data were analyzed by one-way analysis of variance and were considered significant when p<0.05.. We found higher ovarian E2 content (pg/mg ovary: C: 2.11±0.55, BPA50: 12.00±4.28 (p<0.005), BPA500: 29.76±7.85 (p<0.0005), n= 8-14) and lower P4 (pg/mg ovary: C: 531.28±29.57, BPA50: 351.59±54.81 (p<0.05), BPA500: 263.44±56.84 (p<0.005), n= 7-12). T content was not significantly different among groups (pg/mg ovary: C: 17.54±4.57, BPA50: 11.13±3.09, BPA500: 8.47±1.72, n= 6-13). In BPA500, GnRH-I content was increased (pg/mg ovary C: 0.54±0.05, BPA50: 0.69±0.07, BPA500: 0.97±0.07; BPA500: p<0.0005 vs. C, p<0.05 vs. BPA50, n= 9-11). We conclude that in adult neonatally-BPA treated rats ovarian E2 content, increased, and P4 content, decreased, are altered coinciding with the serum levels previously reported. Ovarian T content did not change, unlike serum levels, suggesting changes in metabolism and/or origin of this steroid. In addition, BPA-treatment increased the ovarian GnRH-I content. These results suggest that neonatal exposure to BPA produces a clear alteration in ovarian GnRH-I and steroidogenesis in adulthood. (CONICET-UBA-ANPCYT). 1. Fernandez M et al. Environ Health Perspect 117:757?762, 2009. 2. Fernandez M et al. Environ Health Perspect 118:1217?1222, 2010. 3. NS Bourguignon et al. The Endocrine Society´s 92nd Annual Meeting. S Diego, CA , 2010. Abstract book. P2-59.