title: Ortho-toluene sulphonamide and saccharin in the promotion of bladder cancer in the rat.
abstract: The importance of the contaminant OTS in the promoting activity of commercial saccharin on rat bladder neoplasia was investigated. OTS, OTS-free and OTS-contaminated saccharin were administered in the drinking water or diet for 2 years to groups of rats pretreated  with an intravesical instillation of MNU; OTS alone and OTS-free saccharin were also given to groups of rats not pretreated with MNU. Administration of OTS was not associated with changes in urinary pH, crystalluria or calculus formation, had no effect on the histology of normal rat bladder, and did not increase the incidence of bladder hyperplasia or neoplasia elicited by pretreatment with MNU. No differences could be found between the effect of OTS-free or OTS-contaminated saccharin on bladders of rats pretreated with MNU. These results indicate that OTS contamination played no part in the reported promoting activity of saccharin on the rat bladder. Administration of saccharin did not increase urinary pH, crystalluria or calculus formation, and failed to promote bladder neoplasia after a carcinogenic dose of MNU, though the numbers of proliferative lesions in the bladder were increased.
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D005260:Female; D007668:Kidney / Q000473:pathology; D008770:Methylnitrosourea; D009374:Neoplasms, Experimental / Q000139:chemically induced / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D012439:Saccharin / Q000009:adverse effects*; D013449:Sulfonamides; D014050:Toluene / Q000031:analogs & derivatives*; D014105:Tosyl Compounds / Q000009:adverse effects*; D001743:Urinary Bladder / Q000473:pathology; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced* / Q000473:pathology; D000096926:Benzenesulfonamides
chemical_list: D008770:Methylnitrosourea; D012439:Saccharin; D013449:Sulfonamides; D014050:Toluene; D014105:Tosyl Compounds; C013307:2-toluenesulfonamide; D000096926:Benzenesulfonamides