Grossie V B, Nishioka K
Department of Integrative Biology, University of Texas-Houston Medical School 77030, USA.
Nutr Cancer. 1997;27(1):102-6. doi: 10.1080/01635589709514509.
Substituting ornithine for arginine in total parenteral nutrition (TPN) regimens eliminates the TPN-enhanced growth of the Ward colon tumor. Plasma arginine was increased when tumor growth was increased, suggesting a role for this amino acid. The erythrocyte polyamine content, however, was elevated in rats receiving both TPN regimens, indicating an increased synthesis and availability for tumors receiving arginine- and ornithine-containing regimens. The objective of this study, therefore, was to evaluate the effect of substituting ornithine for arginine in a TPN regimen on the amino acid and polyamine content of the Ward colon tumor compared with that of rats fed chow ad libitum. Male Fischer 344 rats with a transplantable Ward colon tumor implanted subcutaneously were randomized to three groups and fed for four days. One group received a TPN regimen with arginine (1,300 mg/100 ml, ENA), whereas a second group received a regimen with an isonitrogenous substitution of ornithine (ENO). A control group received chow ad libitum. Serum and tumors were evaluated for arginine, ornithine, lysine, and polyamine content. The arginine concentration in the serum and tumor increased when rats received ENA. In contrast, the serum and tumor arginine content for rats receiving ENO was significantly lower than that for rats receiving chow or ENA. Tumor and serum ornithine content was increased severalfold when ornithine was included in the regimen. Tumor polyamine content was not affected by TPN. The results show that serum and tumor arginine content are significantly altered by substituting ornithine for arginine in a TPN regimen. These and previous results suggest that TPN-enhanced growth of the Ward colon tumor when arginine is included in the formulation occurs by a mechanism other than increased polyamine synthesis.
在全胃肠外营养（TPN）方案中用鸟氨酸替代精氨酸可消除TPN促进的沃德结肠肿瘤生长。肿瘤生长加快时血浆精氨酸增加，提示该氨基酸发挥了作用。然而，接受两种TPN方案的大鼠红细胞多胺含量均升高，表明接受含精氨酸和鸟氨酸方案的肿瘤合成增加且可利用性提高。因此，本研究的目的是评估在TPN方案中用鸟氨酸替代精氨酸对沃德结肠肿瘤氨基酸和多胺含量的影响，并与自由摄食普通饲料的大鼠进行比较。皮下植入可移植沃德结肠肿瘤的雄性Fischer 344大鼠被随机分为三组并喂养四天。一组接受含精氨酸的TPN方案（1300 mg/100 ml，ENA），而另一组接受等氮量鸟氨酸替代方案（ENO）。对照组自由摄食普通饲料。评估血清和肿瘤中的精氨酸、鸟氨酸、赖氨酸和多胺含量。大鼠接受ENA时，血清和肿瘤中的精氨酸浓度增加。相比之下，接受ENO的大鼠血清和肿瘤精氨酸含量显著低于接受普通饲料或ENA的大鼠。当方案中包含鸟氨酸时，肿瘤和血清鸟氨酸含量增加了几倍。肿瘤多胺含量不受TPN影响。结果表明，在TPN方案中用鸟氨酸替代精氨酸可显著改变血清和肿瘤精氨酸含量。这些结果以及之前的结果表明，当配方中包含精氨酸时，TPN促进沃德结肠肿瘤生长的机制并非多胺合成增加。
