title: The urinary excretion of bacterial amino-acid metabolites by rats fed saccharin in the diet.
abstract: Administration of a diet containing 7.5% saccharin to adult male rats for 40 days caused a three- to four-fold increase in the daily excretion of indican and rho-cresol. Indican is formed from indole which is a microbial metabolite of tryptophan, whilst rho-cresol is formed by the gut flora from tyrosine. The excretion of phenol, which is also a microbial metabolite of tyrosine, was abolished by saccharin administration for 40 days. Analysis of urines collected at 13, 18 and 24 months during a two-generation cancer bioassay showed that these changes occur throughout the life of saccharin-treated rats. These data indicate that saccharin changes the metabolism of amino acids by the gut flora, leading to an increased formation of products known to have promoting or co-carcinogenic properties.
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D003043:Cocarcinogenesis; D003408:Cresols / Q000652:urine; D004032:Diet; D007200:Indican / Q000652:urine; D007422:Intestines / Q000382:microbiology; D008297:Male; D010636:Phenols / Q000652:urine; D051381:Rats; D011919:Rats, Inbred Strains; D012439:Saccharin / Q000633:toxicity* / Q000652:urine; D014364:Tryptophan / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced
chemical_list: D000596:Amino Acids; D003408:Cresols; D010636:Phenols; C032538:4-cresol; D014364:Tryptophan; D012439:Saccharin; D007200:Indican