Amphibians play an important role as animal models for the study of thyroid hormones. These hormones play an essential regulatory role in vertebrate development, but their involvement in reproduction and sexual development is not well known. My project examined how thyroid hormones affect the production of sex hormones in amphibians. To test this, I treated tissue from the reproductive organs of adult male and female amphibians with thyroid hormone and measure the sex hormone that is produced and released as a result. Most biological studies in endocrinology study endocrine systems in isolation; however, they do not work in isolation.

To determine how thyroid hormones influence the synthesis and release of sex hormones (e.g., estrogen and testosterone) from the gonads of amphibians.

It is important to determine the connections in order to understand the whole. The pathways in the endocrine system do not work in isolation, making it important to discover the points of interaction. There are many contaminants in our environment that target the endocrine system; a compound that affects one pathway might also affect another. By exploring the effect of thyroid hormones on sex hormones, this project could lead to identification of compounds that mimic thyroid hormones and disrupt the reproductive system.

I took a special topics endocrinology course last term. It sparked an interest in the study of this particular topic. I also wanted to gain knowledge of working with lab animals. The species used for this project is an amphibian named Xenopus tropicalis. This frog is commonly used in research, especially for studying the endocrine system. Determining the interactions between hormone systems in Xenopus tropicalis will not only have an application to amphibians but to mammals as well. This project offered me a perfect balance of bench work and animal care.

The most important part of my work was the application it has to the environment. Chemicals like pesticides can have hormone-mimicking effects. It is important to determine the connections between the endocrine system’s hormone pathways in order to determine the full effect that these chemicals have on animal health.

The most fun thing I have done this summer was rearing the tadpoles. I tracked their development from the egg stage through to tadpoles and then to metamorphosis. Growing up in the Maritimes, I have observed tadpoles in the wild at various life stages. To watch every step of their progression has truly been an astounding experience.

The most exciting thing I have done this summer was learning and using new molecular techniques to measure gene expression and hormone production. When I began my studies in biology, methods of this sort seemed advanced, and we only learned them in theory. To actually use these techniques while I am still an undergraduate has been amazing.