Pesticide chlorpyrifos acts as an endocrine disruptor in adult rats causing changes in mammary gland and hormonal balance

VENTURA C; RAMOS NIETO MR; BOURGUIGNON N; LUX-LANTOS V; RODRIGUEZ H; CAO G; RANDI A; COCCA C; NUÑEZ M

JOURNAL OF STEROID BIOCHEMISTRY AND MOLECULAR BIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 156 p. 1 - 9

0960-0760

Endocrine disruptors (EDs) are compounds that interfere with hormone regulation and influence mammarycarcinogenesis. We have previously demonstrated that the pesticide chlorpyrifos (CPF) acts as an ED in vitro,since it induces human breast cancer cells proliferation through estrogen receptor alpha (ERa) pathway. Inthis work, we studied the effects of CPFat environmental doses (0.01 and 1 mg/kg/day) on mammary gland,steroid hormone receptors expression and serum steroid hormone levels. It was carried out using femaleSprague-Dawley 40-days-old rats exposed to the pesticide during 100 days. We observed a proliferatingductal network with a higher number of ducts and alveolar structures. We also found an increased numberof benign breast diseases, such as hyperplasia and adenosis. CPF enhanced progesterone receptor (PgR)along with the proliferating cell nuclear antigen (PCNA) in epithelial ductal cells. On the other hand, thepesticide reduced the expression of co-repressors of estrogen receptor activity REA and SMRT and itdecreased serum estradiol (E2), progesterone (Pg) and luteinizing hormone (LH) levels. Finally, we found apersistent decrease in LH levels among ovariectomized rats exposed to CPF. Therefore, CPF alters theendocrine balance acting as an ED in vivo. Thesefindings warn about the harmful effects that CPF exerts onmammary gland, suggesting that this compound may act as a risk factor for breast cancer.