Alkylphenolic compounds are a widespread family of xenoestrogens. High concentrations of these substances are present in sewage sludge that is spread on arable land and pasture as fertilizer. Because of their known endocrine system-disrupting activity, alkylphenols represent a potential risk for the reproductive health of farm animals. In this study, the impact of p-tert-octylphenol (OP) on the developmental competence of bovine oocytes was evaluated. Endocrine activity of OP was investigated for its effect on estrogen receptors α and β (ERα and ERβ) and progesterone receptor (PR) mRNA levels. Cumulus-oocyte complexes (COCs) were exposed during in vitro maturation to serial concentrations of OP (1–0.0001 μg/ml) and were compared with vehicle-treated controls and a group of COCs treated with 17β-estradiol (E2). A dose-related decrease in the percentage of oocytes that completed maturation after 24 h and in oocyte fertilization competence was observed at doses of OP as low as 0.01 μg/ml. Groups treated with ≥0.001 μg/ml OP showed impaired embryo development. No adverse effects of E2 were observed. In the E2-treated COCs, ERα mRNA was decreased but PR mRNA was upregulated compared with controls. Treatment with 0.001 and 0.0001 μg/ml OP induced a decrease in ERα mRNA, but ERβ and PR mRNA were not affected. Treatment with 0.01 μg/ml OP did not produce changes in the expression of any of the mRNAs studied. OP impairs meiotic progression and developmental competence of bovine oocytes without demonstrating clear estrogen-mimic activity.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.