AhR and ARNT modulate ER signaling.

The aryl hydrocarbon receptor (AhR), in complex with its binding partner ARNT, mediates the cellular response to xenobiotic compounds such as the environmental pollutant dioxin. In addition, the AhR has important regulatory roles in normal physiology. For instance, there is extensive data showing an intricate relationship between the AhR and estrogen receptor (ER) pathways. This review focuses on the regulatory roles of AhR and ARNT, beyond the response to xenobiotics. In particular, the effects of AhR agonists on the estrogen signaling pathways and the role of ARNT as a modulator of ER activity are discussed. (c) 2009 Elsevier Ireland Ltd. All rights reserved.