Arsenic mimics the in vivo estrogen proliferative effects in the uterus and anterior pituitary gland from ovariectomized rats

CROCCO MELISA C; RONCHETTI, SONIA A; CABILLA, JIMENA P; BENZO, YANINA; KELMANSKY, DIANA M; DUVILANSKI, BEATRIZ H.

Chicago

Congreso; 16th International Congress of Endocrinology (ICE/ENDO).; 2014

Inorganic Arsenic (iAs) is one of the most toxic metalloids. Contaminated water consumption-mediated As exposure is one of the greatest environmental health threats worldwide. It has been suggested that iAs could display xenoestrogen activities. A recent report has shown that iAs mimics the proliferative effect of 17β-estradiol (E2) in a hormone-dependent tumor cell line (MCF-7), however, estrogen-like actions were not studied in vivo yet. The aim of this study was to prove whether iAs is able to reproduce E2 physiological response on hormone-dependent tissues as uterus and pituitary gland. Adult female Wistar rats were ovariectomized and exposed to iAs at different doses in drinking water (0.1 or 1 ppm) for 30 days. Control groups received free access to tap water without As (negative control) or were implanted s.c. with 500 µg E2 capsule (positive control). Animals were weighed once a week. Estrous cycle and water consumption were determined daily. The glandular area and epithelial height were determined by image analysis of optic microscopy in separate sections of the uterus (Control, n = 5; iAs 0.1 ppm, n = 6; 1 ppm iAs, n = 6; E2, n = 5). The estimated means were obtained by ANOVA, and a posteriori comparisons were performed using the Tukey method. Protein expression was assessed by western blot. Both iAs doses (0.1 and 1 ppm) were able to increase the frequency of proestrus and estrus. The percentage of glandular area regarding uterine endometrium area was significantly greater in animals treated with 0.1 ppm As and E2 (Control: 1.09%; 0.1 ppm iAs: 5.17% *; 1 ppm iAs: 1.87 %; E2: 10.53% *; *p