Effects of Total Parenteral Nutrition on Tumor Growth, and Plasma and Tumor Free Amino Acids in Tumor-bearing Rats

This study was undertaken to reveal the effects of total parenteral nutrition (TPN) on tumor growth and plasma and tumor free amino acids in male Donryu rats having a transplanted Sato lung cancer. Animals were fed for 7 days and were divided into several groups as follows: 1. regular diet, 2. restricted regular diet, 3. protein free diet, 4.5 % glucose, 5. 21% glucose and 6 to 9. (TPN groups) 21 % glucose and different amino acids. Positive nitrogen balance was gained in TPN groups and body weight gain was observed except in a few cases. There was no stimulation in tumor growth by TPN, which was similar to the regular diet group. Plasma E/N ratio and percentage of blanched chain amino acids were decreased in malnourished rats, but E/N ratio and total amino acid concentration were increased in TPN and the amino acid pattern was similar to the regular diet group. In tumor amino acids analysis, there were no evident deviations of amino acid patterns from plasma amino acids. Constant amino acid trapping was revealed in tumor tissues. Amino acid imbalance therapy was suggested to be effective in the case of deficiencies of Tyr. Glu. and Asp. and high concentration of BCAA.