EFFECT OF L-TRYPTOPHAN AND SODIUM SACCHARIN ON URINARY-TRACT CARCINOGENESIS INITIATED BY N-[4-(5-NITRO-2-FURYL)-2-THIAZOLYL]FORMAMIDE

  • 1 January 1981
    • journal article
    • research article
    • Vol. 41  (8) , 3100-3103
Abstract
The effect of sodium saccharin (SAC) or L-tryptophan (LT) on urinary bladder carcinogenesis initiated by feeding N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) for 4 wk as 0.2% of the diet to male F344 weanling rats was evaluated. SAC was fed as 5% of the diet and LT was 2% of the diet. FANFT fed for 4 wk followed by 100 wk of control diet did not produce any carcinomas; 1 of 25 rats developed a bladder papilloma. Of 26 rats fed SAC for 100 wk after FANFT, 2 developed papillomas and 5 developed carcinomas (P < 0.03). Of 26 rats fed LT for 100 wk after FANFT, 3 developed papillomas and 2 developed carcinomas (P > 0.1). Eight rats fed FANFT for 72 wk all developed bladder carcinomas but rats fed control diet alone, control diet with SAC or control diet with LT did not develop any bladder tumors. Scanning electron microscopic examination at wk 104 of the experiment showed the presence of pleomorphic microvilli on the bladder surface of some rats fed SAC or LT whether following 4 wk of control diet alone or 4 wk of FANFT. Four weeks of FANFT feeding, a lower dose than used previously in these studies, appears to be a subcarcinogenic level. The promoting activity of SAC is demonstrated with statistical significance. The results with LT were not statistically significant.