Expression Profiles of Reproduction and Thyroid Hormone Related Transcripts in the Brains of Chemically Induced Intersex Frogs

The study examined the effects of endocrine-disrupting chemicals, finasteride and fadrozole, on the brain gene expression of Silurana tropicalis frogs, focusing on reproduction- and thyroid hormone-related transcripts. Finasteride, an anti-androgen, increased mRNA levels of several genes, including aromatase and estrogen receptors, in intersex frogs, indicating altered gene expression linked to increased testosterone levels. Fadrozole, an anti-estrogen, did not change mRNA levels but reduced aromatase activity. The research highlighted the complex interaction between thyroid hormone-responsive genes and androgen status, suggesting a crosstalk between these systems in amphibians. The study involved eight individual brains per phenotype per treatment, providing insights into the neuroendocrine effects of these chemicals on amphibian brain development and the environmental risks posed by chemical pollutants.