Exposure to Inorganic Arsenite during pregnancy alters reproductive parameters in postpartum rats

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 338-354-Physiological Impacts of Endocrine Disrupting Chemicals
Basic/Translational
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-347
Nadia Bourguignon*1, Diego Rodriguez1, Maria Marta Bonaventura1, Victoria Adela Lux-Lantos2 and Carlos Libertun3
1Instituto de Biología y Medicina Experimental, Buenos Aires, Argentina, 2IBYME, Buenos Aires, Argentina, 3IBYME-CONICET, Buenos Aires, Argentina
Exposure to Inorganic Arsenite during pregnancy alters reproductive parameters in postpartum rats.

 

Bourguignon N1, Rodríguez D1, Bonaventura MM1, Lux-Lantos V1, Libertun C1, 2

1 IBYME-CONICET, V de Obligado 2490. Buenos Aires. 2Dep. Physiology.  Fac. Medicine, Universidad de Buenos Aires. Argentina.

nsbourguignon@yahoo.com.ar

Inorganic arsenic (A) is a soil and ground water contaminant with worldwide distribution. It is highly toxic and a proved carcinogenic in humans. It has also been described as an endocrine disruptor impacting the metabolic and reproductive axes, although the mechanisms have not been elucidated. Here, we investigated the effects of A in drinking water in pregnant rats on the reproductive axis, during pregnancy and until 10 weeks after delivery.

Young, previously virgin, pregnant Sprague-Dawley rats were treated with sodium arsenite in drinking water: 5 (A5) or 50 (A50) ppm in distilled water or distilled water as control (C), from gestation day 1 (determined by the presence of vaginal sperm plug) to sacrifice (8-10 weeks post-partum). Standard chow was given ad libitum. Body weight (BW) was recorded. Studies were performed according to protocols for animal use approved by the Institutional Animal Care and Use Committee which follows NIH guidelines.

Body weight (BW) was recorded during pregnancy and thereafter. One month after delivery estrous cycles started to be recorded and a GnRH test was evaluated at 7-8 weeks postpartum (100 ng GnRH intrajugular, serum LH and FSH at 0, 15 and 50 min were quantified by RIA). Rats were sacrificed by quick decapitation on the morning of estrus and PRL, E2 and P4 determined by RIA in trunk blood. Ovarian weight was recorded. Results are expressed as means ± S.E.M (n). Differences between means were analyzed by Chi square or one-way ANOVA. P<0.05 was considered statistically significant.

BW was reduced at 21 days of pregnancy in A50 (g: C=352.2±7.8 (12); A5=352.8±6.8 (14); A50=301.4±7.9 (11), p< 0.001, A50 vs. C, A5). Two months after delivery these differences disappeared.  In postpartum rats, estrous cycles were altered in both A groups, with an increase in the number of anestrous (p<0.005). In treated animals, the GnRH test was unchanged after any treatment. However basal serum FSH was increased in the A50 group (ng/ml: C=1.26±0.09 (6), A5=2.01±0.26 (8); A50=2.49±0.49 (8) p<0.05 A50 vs. C).

In trunk blood, PRL was lower in A50 (ng/ml: C=20.42±3.4 (6), A5=11.98: ±2.27 (7), A50=11.55: ±2.01 (7), p<0.05 A50 vs. C) and E2 was also lower (pg/ml: C=19.46±6.15 (6); A5=7.72±2.24 (7) A50=6.56±1.34 (8), p<0.05 A50 vs. C). P4 serum levels and ovarian weight were unchanged.

We conclude that A in drinking water during pregnancy has a long lasting effect in the reproductive axis in the rat.

Nothing to Disclose: NB, DR, MMB, VAL, CL

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: CONICET-UBA-ANPCYT