title: Alterations of the intestinal microflora by diet, oral antibiotics, and Lactobacillus: decreased production of free amines from aromatic nitro compounds, azo dyes, and glucuronides.
abstract: F344 rats were fed compounds containing a nitro, azo, or amine-glucuronide group-2-nitronaphthalene (CAS: 581-89-5), 2-nitrofluorene (CAS: 607-57-8; 2-nitro-9H-fluorene), 4-phenylazo-2-naphthol (CAS: 6410-10-2; 1-[(4-nitrophenyl)azo]-2-naphthol), and 2-naphthylamine-N-D-glucuronide--and the formation of free amines was measured in the feces. The effects of diet (mean vs. grain), administration of antibiotic, and the feeding of Lactobacillus acidophilus were evaluated. Meat-fed rats given 2-nitronaphthalene had approximately 4 times higher concentration of free amines in their feces as compared to the concentration in grain-fed rats. In a similar experiment with 2-naphthylamine-N-D-glucuronide, the meat-fed animals had approximately 1.5 times more of the free amines and 50% less of the conjugates in their feces. When meat-fed animals were given L. acidophilus with 2-nitrofluorene or 2-naphthylamine-N-D-glucuronide, they had significantly lower free amines and higher concentrations of conjugates in their feces than did the meat-fed controls. Similarly, erythromycin or tetracycline decreased the fecal amine production in meat-fed animals that had received 2-nitrofluorene or 4-phenylazo-2-naphthol. In another experiment, erythromycin inhibited the production of free amines from 2-naphthylamine-N-D-glucuronide in rats fed a high-fat diet. Studies of fecal enzymes revealed lower levels of beta-D-glucuronidase, nitroreductase, and azoreductase in grain-fed rats and in meat-fed animals also given antibiotics or lactobacilli. These experiments showed that intestinal flora have the ability to convert exogenously administered aromatic nitro and azo compounds and an amine-glucuronide compound to free amines. The rate of these conversions was affected by diet and by oral administration of antibiotics and lactobacilli.
mesh_terms: D000588:Amines / Q000378:metabolism*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001391:Azo Compounds / Q000494:pharmacology*; D004396:Coloring Agents / Q000494:pharmacology; D004032:Diet; D004917:Erythromycin / Q000494:pharmacology; D005243:Feces / Q000382:microbiology; D005965:Glucuronates / Q000378:metabolism*; D007422:Intestines / Q000382:microbiology*; D007779:Lactobacillus acidophilus / Q000502:physiology*; D008297:Male; D009574:Nitro Compounds / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D000588:Amines; D000900:Anti-Bacterial Agents; D001391:Azo Compounds; D004396:Coloring Agents; D005965:Glucuronates; D009574:Nitro Compounds; D004917:Erythromycin; D010088:Oxidoreductases; D013752:Tetracycline