Transcriptomic Signatures Confirm Conserved Molecular Responses to Glucocorticoid Receptor Agonists in Fathead Minnow (Pimephales promelas)

Differential gene expression analysis revealed substantial overlap in affected genes between the two compounds, supporting their shared mechanism of action. Transcriptomic points of departure (tPODs) were calculated to identify concentrations at which early transcriptomic responses would likely occur.

Functional enrichment analysis identified activated biological pathways and enabled the calculation of biological pathway altering concentrations (BPACs). Both compounds significantly altered pathways related to glucocorticoid activity, with fluticasone showing higher potency in most of the pathways. The significant overlap in differentially expressed genes and enriched pathways provides evidence that transcriptomic profiling can effectively detect shared mechanisms of action between related compounds.