The Effects of Exposure to β-Estradiol on Metabolic Rate and Malate Dehydrogenase Activity in Lithobates catesbeianus
Loading...
Authors
Hagan, Zoe
Allie, Hayden
Date of Issue
2025-04-25
Type
Presentation
Language
en_US
Subject Keywords
Other Titles
Abstract
Decline of amphibian populations can be partially attributed to pollution of aquatic habitats. Amphibians readily absorb soluble molecules from their environment through their skin, making them sensitive to pollutants. Estrogen (β-Estradiol) is a female steroid hormone that has become a micropollutant in American water systems. As a pollutant, estrogen has been found to cause reproductive, muscular, and immune system dysfunctions in amphibians, but its effect on metabolism is yet to be explored. One of estrogen's many functions is binding with estrogen receptors on promoter sequences in the Nuclear Respiratory Factor-1(NRF-1) gene, promoting transcription. The protein translated from NRF-1 is a cofactor required to produce mitochondrial transcription factor A (TFAM). TFAM transcribes mitochondrial DNA and produces the electron transport subunits used in oxidative phosphorylation (OXPHOS). The production of TFAM and OXPHOS subunits causes mitochondria to increase metabolic rate and divide. In this study, bullfrogs (Lithobates catesbeianus) will be divided into a control group and two experimental groups (exposed to 0, 15, or 30 ng/L of estrogen, respectively). Metabolic rate will be measured before exposure, two weeks after exposure, and 4 weeks after exposure. Malate dehydrogenase (MDH) is an enzyme that can be used as a marker for a tissue’s ability to utilize the citric acid cycle. After 4 weeks of exposure, MDH assays will be performed in muscle tissues to determine if enzymatic activity has changed. If estrogen increases TFAM production in bullfrogs, we hypothesize that their metabolic rate and MDH activity will be higher than observed in controls.