Sidransky H, Garrett C T, Murty C N, Verney E, Robinson E S
Cancer Res. 1985 Oct;45(10):4844-7.
The ingestion of an elevated level (2%) of L-tryptophan (TRP) in a purified diet was investigated to determine whether it would influence the induction of gamma-glutamyltranspeptidase (GGT)-positive foci in the livers of rats exposed to a hepatocarcinogen. Subtotal hepatectomies were performed, and 18 h later, the rats were given injections i.p. of diethylnitrosamine (30 mg/kg). Ten days later, groups of male rats were placed on choline-supplemented (CS), CS + TRP, choline-deficient (CD), or CD + TRP diets for 10 wk. In two separate experiments, the rats fed the CS + TRP diet or the CD diet developed more and larger GGT + foci than did rats fed the CS diet. Rats fed the CD + TRP diet revealed similar changes to those found in rats fed the CD diet. The liver weights of the rats fed the CD or the CD + TRP diet were greater than those of rats fed the CS or the CS + TRP diet. Hepatic GGT activity was somewhat elevated in rats fed the CS + TRP diet and markedly elevated in rats fed the CD or the CD + TRP diet. Hepatic ornithine decarboxylase activity was increased in rats fed the CD + TRP diet. The results suggest that increased dietary tryptophan has a promoting effect on liver carcinogenesis as measured by the induction of GGT + foci in the livers of rats exposed to diethylnitrosamine. A potentiating effect by tryptophan was not observed in the livers of rats fed a CD diet.
研究了在纯化饮食中摄入高水平（2%）的L-色氨酸（TRP）是否会影响暴露于肝癌致癌物的大鼠肝脏中γ-谷氨酰转肽酶（GGT）阳性灶的诱导。进行了部分肝切除术，18小时后，给大鼠腹腔注射二乙基亚硝胺（30毫克/千克）。10天后，将雄性大鼠分组，分别给予补充胆碱（CS）、CS + TRP、胆碱缺乏（CD）或CD + TRP饮食，持续10周。在两个独立实验中，与喂食CS饮食的大鼠相比，喂食CS + TRP饮食或CD饮食的大鼠产生了更多更大的GGT + 灶。喂食CD + TRP饮食的大鼠显示出与喂食CD饮食的大鼠相似的变化。喂食CD或CD + TRP饮食的大鼠肝脏重量大于喂食CS或CS + TRP饮食的大鼠。喂食CS + TRP饮食的大鼠肝脏GGT活性略有升高，而喂食CD或CD + TRP饮食的大鼠肝脏GGT活性显著升高。喂食CD + TRP饮食的大鼠肝脏鸟氨酸脱羧酶活性增加。结果表明，增加饮食中的色氨酸对暴露于二乙基亚硝胺的大鼠肝脏致癌作用有促进作用，以肝脏中GGT + 灶的诱导来衡量。在喂食CD饮食的大鼠肝脏中未观察到色氨酸的增强作用。
