Sasaki Emi, Ohta Yoshiji
Department of Biochemistry, School of Medicine, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
J Nutr Sci Vitaminol (Tokyo). 2005 Dec;51(6):471-4. doi: 10.3177/jnsv.51.471.
We examined the changes in serum, liver, kidney, brain, and muscle L-tryptophan (Trp) levels in rats with puromycin aminonucleoside (PAN) nephrosis following oral Trp administration in order to elucidate the fate of elevated Trp in the blood of PAN nephrotic rats with oral Trp administration in their body. Before administration, nephrotic rats had higher liver and kidney Trp contents and lower serum Trp concentration than non-nephrotic rats. At 15 min after oral administration of Trp (100 micromol/kg body weight), PAN nephrotic rats had a much higher amount of liver Trp than non-nephrotic rats but there were no differences in increased amounts of serum, kidney, brain, and muscle Trp between the two groups. At 30 min after oral Trp administration, PAN nephrotic rats had a lower increased amount of serum Trp than non-nephrotic rats and had no increase in liver Trp content, although the increased amounts of Trp in other tissues were similar in both groups. At 30 min after oral Trp administration, liver tryptophan 2,3-dioxygenase activity increased approximately 2 fold in PAN nephrotic rats. These results indicate that elevated Trp in the blood of PAN nephrotic rats with oral Trp administration is transported mainly into the liver rapidly and then the transported Trp is actively metabolized by activated tryptophan 2,3-dioxygenase in the tissue.
为了阐明口服色氨酸（Trp）后嘌呤霉素氨基核苷（PAN）肾病大鼠体内血液中升高的色氨酸的去向，我们检测了口服Trp后PAN肾病大鼠血清、肝脏、肾脏、脑和肌肉中L-色氨酸（Trp）水平的变化。给药前，肾病大鼠肝脏和肾脏中的Trp含量高于非肾病大鼠，而血清Trp浓度低于非肾病大鼠。口服Trp（100微摩尔/千克体重）后15分钟，PAN肾病大鼠肝脏中的Trp含量比非肾病大鼠高得多，但两组血清、肾脏、脑和肌肉中Trp增加量没有差异。口服Trp后30分钟，PAN肾病大鼠血清Trp增加量低于非肾病大鼠，肝脏Trp含量没有增加，尽管两组其他组织中Trp增加量相似。口服Trp后30分钟，PAN肾病大鼠肝脏色氨酸2,3-双加氧酶活性增加约2倍。这些结果表明，口服Trp的PAN肾病大鼠血液中升高的Trp主要迅速转运到肝脏，然后转运的Trp在组织中被激活的色氨酸2,3-双加氧酶积极代谢。
