The aryl hydrocarbon receptor (AhR) is responsible for the toxic effects of environmental pollutants such as dioxin, but little is known about its normal physiological functions. Li et al. (2011) now show that specific dietary compounds present in cruciferous vegetables act through the AhR to promote intestinal immune function, revealing AhR as a critical link between diet and immunity.

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor; the AhR Per-AhR/Arnt-Sim (PAS) domain binds ligands. We developed homology models of the AhR PAS domain to characterize previously observed intra- and interspecies differences in ligand binding using molecular docking. In silico structure-based virtual ligand screening using our model resulted in the identification ...

The aryl hydrocarbon receptor (AHR) binds environmental toxins and mediates immune regulation. The tryptophan metabolite kynurenine has now been identified as an endogenous ligand of the human AHR constitutively produced by gliomas and other types of cancer via tryptophan-2,3-dioxygenase (TDO), thereby suppressing antitumor immune responses via the AHR. Thus, this pathway represents an importan...

The aryl-hydrocarbon receptor (AHR), a ligand activated PAS superfamily transcription factor, mediates most, if not all, of the toxicity induced upon exposure to various dioxins, dibenzofurans, and planar polyhalogenated biphenyls. While AHR-mediated gene regulation plays a central role in the toxic response to dioxin exposure, a comprehensive understanding of AHR biology remains elusive. AHR-m...

The transition to reproductive senescence involves changes in neuroendocrine and ovarian functions, and is accelerated by activation of the aryl hydrocarbon pathway by environmental toxicants such as 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD). In this article, studies which provide evidence as to the possible mechanisms by which the aryl hydrocarbon receptor (AhR) acts in this capacity (i.e. d...

Unknown, but the effects seem limited. Rats homozygous for the mutant allele have a dramatically increased LD50 for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and PCDD (penta-), but not HCDD (hexa-). Overall, the tissue distribution and excretion of TCDD in rats homozygous for the AhR mutation is similar to that of the Long-Evans rat, which was used as a dioxin-sensitive control strain. Reprodu...

Even before the first vertebrates appeared on our planet, the aryl hydrocarbon receptor (AHR) gene was present to carry out one or more critical life functions. The vertebrate AHR then evolved to take on functions of detecting and responding to certain classes of environmental toxicants. These environmental pollutants include polycyclic aromatic hydrocarbons (e.g., benzo[a]pyrene), polyhalogena...