Meeting Abstract
Many pharmaceuticals, upon entering the environment via wastewater treatment plants, are considered endocrine disrupting chemicals (EDCs). Through both direct and indirect effects, EDCs can impact the functioning of critical endocrine axes, including the hypothalamus-pituitary-gonadal (HPG) axis, and the hypothalamus-pituitary-adrenal (HPA) axis. The synthetic estrogen found in oral contraceptives, 17α -Ethinylestradiol (EE2), is considered an estrogenic EDC and is often detected in sewage effluent. Both aquatic and terrestrial animals can be exposed to EE2 in the environment with potential effects on stress physiology, namely the levels of the stress hormone corticosterone (CORT). We observed the effects of EE2 on baseline and stress-induced CORT levels in captive zebra finches (Taeniopygia guttata). We used three levels of EE2 exposure, 0 ng (control); 4 ng, which is a level found in streams near wastewater effluent sites; and 100 ng, which serves as a higher level not recorded in nature. Birds were exposed to their respective treatments every other day for three weeks before stress tests. We induced the stress response by fasting the birds for 4 hours and collected pre-and post-fasting blood samples. We found that baseline CORT responses were increased in 4 ng EE2 treated females in comparison to control and 100 ng EE2 treated females. EE2 treatment did not influence male baseline and stress-induced CORT levels. Female baseline CORT levels could be used to indicate environmental estrogenic EDC exposure, but more research is necessary to determine if increased CORT responses in females are observed in other species after EE2 exposure.
