IN-VIVO PRODUCTION AND ENZYME-INDUCING ACTIVITY OF INDOLE[3,2-B] CARBAZOLE

Indolo[3,2-b]carbazole (ICZ) is a potent Ah receptor agonist produced during the oligomerization of indole-3-carbinol (I3C), a breakdown pro duct of the glucobrassicin present in food plants of the Brassica genu s. Levels of ICZ present in the feces, urine, gastrointestinal tracts, and livers of rats fed on I3C- or cabbage-supplemented basal diet wer e 16-fold to over 100-fold higher than levels for animals on the basal diet alone. Levels of ICZ significantly lower than the basal levels f or conventional rats were present in feces of germfree rats, indicatin g that gut bacteria are important for the production of ICZ from essen tial dietary constituents. Low levels of ICZ in extracts of human fece s were also detected. The results suggest further that ICZ by itself m ay not be responsible for the enzyme-inducing activity of orally admin istered I3C or its precursors.