The insecticide chlorpyrifos modifies the expression of genes involved in the PXR and AhR pathways in the rainbow trout, Oncorhynchus mykiss

Chlorpyrifos (CPF) is an organophosphate pesticide, commonly detected in water and food. Despite CPF toxicity on aquatic species has been extensively studied, few studies analyze the effects of fish transcriptional pathways. The Pregnane X receptor (PXR) a nuclear that activated by binding to wide variety ligands regulates transcription enzymes involved metabolism transport many endogenous exogenous compounds. We evaluated mRNA expression PXR-regulated-genes (PXR, CYP3A27, CYP2K1, ABCB1, UGT, ABCC2) intestine liver rainbow trout, Oncorhynchus mykiss, exposed vivo environmentally relevant concentration. Our results demonstrate PXR PXR-regulated genes increased O. mykiss upon exposure CPF. Additionally, we impact other cellular pathway xenobiotic metabolism, Aryl Hydrocarbon Receptor (AhR) pathway, activity different biotransformation (CYP2M1, GST, FMO1, or cholinesterases (ChEs)). In contrast PXR, AhR, its target gene CYP1A, are reduced exposure. Furthermore, ChE CYP1A activities significantly inhibited CPF, both liver. activates liver, with more profound effect intestine. Likewise, our support regulatory crosstalk between AhR pathways, where induction coincides downregulation AhR-mediated