Incidence of Mouse Bladder Tumors following Implantation of Paraffin Pellets Containing Certain Tryptophan Metabolites.

Pellets of paraffin wax implanted into the lumen of the bladder of 38 mice induced one carcinoma. An equally low incidence of carcinomas was induced with paraffin wax pellets containing 15-20 per cent suspensions of 8-hydroxyquinoline or quinaldic acid, 8-hydroxyquinaldic acid, xanthurenic acid, the 8-methyl ether of xanthurenic acid, 4,8-quinolinediol, L-kynurenine sulfate, 3-hydroxy-L-kynurenine, and 3-hydroxyanthranilic acid, all metabolites of tryptophan. The inability to produce pellets of uniform composition containing these test substances was demonstrated. Paper Chromatographie methods revealed that most of these compounds remained in the paraffin vehicle in vivofor as long as 342 days. It was concluded that paraffin is not a satisfactory vehicle in which to test these urinary tryptophan metabolites for bladder carcinogenicity.