Fukushima S, Friedell G H, Jacobs J B, Cohen S M
Cancer Res. 1981 Aug;41(8):3100-3.
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 weeks 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 weeks followed by 100 weeks of control diet did not produce any carcinomas; one of 25 rats developed a bladder papilloma. Of 26 rats fed SAC for 100 weeks after FANFT, two developed papillomas, and five developed carcinomas (p less than 0.03). Of 26 rats fed LT for 100 weeks after FANFT, three developed papillomas, and two developed carcinomas (p greater than 0.1) Eight rats fed FANFT for 72 weeks 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 of Week 104 of the experiment showed the presence of pleomorphic microvilli on the bladder surface of some rats fed SAC of LT whether following 4 weeks of control diet alone or 4 weeks of FANFT. Four weeks of FANFT feeding, a lower dose than used previously in our studies, appears to be a subcarcinogenic level. Under these experimental conditions, the promoting activity of SAC is demonstrated with statistical significance. The results with LT were not statistically significant.
评估了糖精钠（SAC）或L-色氨酸（LT）对雄性F344断奶大鼠膀胱癌发生的影响。这些大鼠被喂食含0.2% N-[4-(5-硝基-2-呋喃基)-2-噻唑基]甲酰胺（FANFT）的饲料4周，随后分别喂食含5% SAC、2% LT的饲料或对照饲料100周。仅喂食4周FANFT后再喂食100周对照饲料的大鼠未产生任何癌症；25只大鼠中有1只发生了膀胱乳头状瘤。在FANFT后喂食100周SAC的26只大鼠中，2只发生了乳头状瘤，5只发生了癌症（p<0.03）。在FANFT后喂食100周LT的26只大鼠中，3只发生了乳头状瘤，2只发生了癌症（p>0.1）。喂食72周FANFT的8只大鼠均发生了膀胱癌，但仅喂食对照饲料、对照饲料加SAC或对照饲料加LT的大鼠未发生任何膀胱肿瘤。实验第104周的扫描电子显微镜检查显示，无论在单独喂食4周对照饲料还是4周FANFT后，喂食SAC或LT的一些大鼠膀胱表面存在多形性微绒毛。4周的FANFT喂食，这一剂量低于我们之前研究中使用的剂量，似乎处于亚致癌水平。在这些实验条件下，SAC的促癌活性具有统计学意义。LT的结果无统计学意义。
