Grantee Research Project Results
The Effects of Endocrine Disruptors on the Sexual Differentiation of the Brain and Gonads of Larval Oak Toads (Bufo quercicus) from the Florida Everglades
EPA Grant Number: U916214Title: The Effects of Endocrine Disruptors on the Sexual Differentiation of the Brain and Gonads of Larval Oak Toads (Bufo quercicus) from the Florida Everglades
Investigators: Ganser, Lisa R.
Institution: University of Miami
EPA Project Officer: Hahn, Intaek
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $96,172
RFA: Minority Academic Institutions (MAI) Fellowships for Graduate Environmental Study (2003) RFA Text | Recipients Lists
Research Category: Biology/Life Sciences , Fellowship - Natural and Life Sciences , Academic Fellowships
Objective:
The objective of this research project is to study the effects of endocrine disruptors on the sexual differentiation of the brain and gonads of larval Oak Toads, Bufo quercicus, from the Florida Everglades. The endocrine system serves as one of the main control systems of the body. During the larval period, hormones help to organize bipotential reproductive tissues in the brain and the gonads into their male or female forms. It is during this critical period of organization that manmade chemicals or endocrine disruptors in the environment, may disrupt the normal cascade of hormonal events that govern the function and form of reproductive tissues. These endocrine disruptors, often found in pesticides and industrial wastes, have been known to affect the morphology of the gonads as well as the mating behaviors of exposed animals.
Approach:
I will collect Oak Toads, B. quercicus, from various sites in South Florida. I will breed the toads and sample animals at various stages of the larval period. Histological sections will be made of the gonads and the brain at various larval stages. The timing of sexual differentiation of the gonads will be determined by the stage of the larval period at which the gonad appears to be a fully formed ovary or testis. Immunohistochemistry methods will be used to determine any sexual differences in brain morphology by assessing any variations in arginine vasotocin (AVT) receptor populations in the areas of the brain responsible for mate calling. After the timing of sexual differentiation of the gonads and any sexual differences in brain structure are determined, new Oak Toad specimens will be treated with the endocrine disrupting pesticide, atrazine. Using the histological methods mentioned above, I will assess any affects of atrazine on the sexual differentiation of the brain and gonads of the Oak Toad.
Supplemental Keywords:
fellowship, endocrine disruptors, Oak Toads, Bufo quercicus, Florida Everglades, Floride, FL, arginine vastocin, AVT, endocrine system, atrazine, pesticides, sexual differentiation., Health, RFA, Scientific Discipline, Geographic Area, State, Biology, Environmental Chemistry, Endocrine Disruptors - Human Health, endocrine disruptors, Biochemistry, Endocrine Disruptors - Environmental Exposure & Risk, estrogen response, frog embryo study, EDCs, microbial degradation, pesticides, aquatic ecosystem, atrazine, wastewater, chlorpyrifos, sex differences, endocrine disrupting chemicals, Florida EvergladesProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.