Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Robert Dearth

Second Advisor

Dr. Erin Schuenzel

Third Advisor

Dr. Mario Gil


Exposure to endocrine-disrupting chemicals has been associated with an increased risk of anxiety-like behavior at various life stages. Levonorgestrel (LNG), a synthetic contraceptive, could potentially alter steroidal regulated brain development based on the findings of this thesis. In-silico measurements were used for comparing LNG, which had been found in surface water, to chemical databases to predict the bioavailability, half-life, and estrogen binding potential. Zebrafish (Danio rerio) for illuminating the effects of LNG exposure during early zebrafish embryonic development, similar to fetal development, on behavior was investigated. Our data suggests exposure in a dose-dependent manner of LNG can potentially alter steroid-mediated early development as indicated by displaying an anxiety-like behavioral phenotype in both the locomotive and thigmotaxis behavioral assays at 5 days post-fertilization. Furthermore, embryonic zebrafish displayed an increase in heart rate phenotype at 2 dpf. Altogether, this thesis uncovered LNG sensitive period of development in embryonic zebrafish.


Copyright 2020 Austin Fuentes. All Rights Reserved.