Modification of rat caecal microbial biotransformation activities by dietary saccharin.
Male Sprague-Dawley rats were fed a purified fibre-free diet containing 5% (w/w) sodium saccharin for 4 weeks or 20 weeks and changes in caecal bacterial numbers and enzyme activities (endogenous ammonia production, beta-glucosidase, beta-glucuronidase, nitrate reductase, nitroreductase, aryl sulphatase) determined in vitro. Saccharin treatment gave marked caecal enlargement but had no effect on bacterial concentration at either treatment period, and significantly decreased beta-glucuronidase, nitrate reductase and sulphatase activities/g caecal contents. The incubation of a suspension of caecal contents from control rats with saccharin (75 mM) in vitro inhibited beta-glucuronidase and nitrate reductase activities, and ammonia production from endogenous substrates. Such changes may decrease the rate of formation of toxic bacterial products in the hindgut.
D000641:Ammonia / Q000378:metabolism; D000818:Animals; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism; D001711:Biotransformation; D002432:Cecum / Q000187:drug effects / Q000382:microbiology*; D005966:Glucuronidase / Q000032:analysis; D008297:Male; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000032:analysis; D009601:Nitroreductases; D010088:Oxidoreductases / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D012439:Saccharin / Q000633:toxicity*
D000641:Ammonia; D010088:Oxidoreductases; D009565:Nitrate Reductases; D009601:Nitroreductases; D050901:Nitrate Reductase; D005966:Glucuronidase; D012439:Saccharin