EFFECT OF ARGININE-ENRICHED TOTAL PARENTERAL-NUTRITION ON THE HOST-TUMOR INTERACTION IN CANCER-BEARING RATS

By using a transplantable Yoshida sarcoma in a rat total parenteral nutrition model, we measured the effectiveness of an arginine-enriched amino acid solution (AI-82) in terms of leucine kinetics and nitrogen balance as indicators of host-tumor nutrition interaction compared with that of a conventional amino acid solution (Proteamin12). When tumor-bearing rats received isocaloric total parenteral nutrition solutions for 7 days, AI-82 significantly improved host nitrogen balance and significantly decreased the tumor-nitrogen trap throughout the experimental period. Leucine kinetics of whole body and tissues were also determined by a 4-hour continuous infusion of each total parenteral nutrition solution containing C-14-leucine. Significantly increased whole-body leucine oxidation (p < .01) without an increase in leucine release from normal tissues was observed in the AI-82 group. Total incorporation of C-14-leucine into whole muscle was significantly elevated (p < .05) without changes in muscle protein degradation in the AI-82 group. In the whole tumor, AI-82 tended to decrease total incorporation of C-14-leucine, but there was no difference in leucine release caused by protein breakdown between the two groups. These findings suggest that AI-82 can improve the nutritional status of the host over that of the tumor.