In addition, independent of GPCRs or MCT1 pathways, butyrate activates the AhR, modulating the interaction between diet, GM and host (151, 184, 185) therefore is reduced in IBD Thus, butyrate, by inhibiting HDACs, increases CYP1A1 expression in a AhR-dependent manner in Caco-2 and HT-29 cells (188). The gene discussed is AHR; the disease is inflammatory bowel disease.