We are interested in understanding the role of the aryl hydrocarbon receptor (AHR) in human biology and disease and how the AHR signalling pathway interconnects with the estrogen receptor and nuclear factor (erythroid-derived 2)-like 2, also known as NFE2L2 or Nrf2. Numerous natural substances, endogenous chemicals and environmental contaminants activate the AHR, with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin) being the most potent. Detectable levels of dioxins are present in all humans, and laboratory animals exposed to TCDD exhibit a wide spectrum of toxic responses that are dependent on AHR.