AHR and hyperinsulinemic hypoglycemia, familial, 4: The administration of the tryptophan metabolite 6-formylindolo(3,2-b) carbazole (FICZ), an endogenous AHR agonist, exacerbated disease (76), while systemic administration of TCDD had the same ameliorating effect on disease progression as AHR-deficiency (77).