Thyroid Hormone Disruption and Reproduction

Several classes of environmental contaminants have been identified as having the ability to alter thyroid hormone signaling. Though thyroid hormones are most well recognized for their roles in regulating somatic growth and development, they also have roles in a variety of other physiological processes. Our lab is particularly interested in the impacts of thyroid disruption on reproduction as there is evidence of crosstalk between the endocrine axes that regulate thyroid and sex steroid hormones. Thus, we have completed several experiments aimed at uncovering the impacts of adult and early life stage thyroid disruption on reproduction. Our results show that early life stage thyroid disruption leads to significant reductions in fecundity. Interestingly, these reductions in fecundity are related to the exposure history of male fish, rather than female fish suggesting that early life stage thyroid disruption impacts key aspects of male reproduction. Through transcriptomic studies, conducted in collaboration with Dr. Matt Hale, we have found that these males experience alterations in the expression of genes associated with neurogenesis and sex steroid signaling in the brain. Current work is aimed at determining whether the sexual behavior of these male fish has been altered.