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 nu trition model, we measured the effectiveness of an arginine-enriched a mino acid solution (AI-82) in terms of leucine kinetics and nitrogen b alance 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 sig nificantly decreased the tumor-nitrogen trap throughout the experiment al period. Leucine kinetics of whole body and tissues were also determ ined by a 4-hour continuous infusion of each total parenteral nutritio n solution containing C-14-leucine. Significantly increased whole-body leucine oxidation (p < .01) without an increase in leucine release fr om 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 pro tein breakdown between the two groups. These findings suggest that AI- 82 can improve the nutritional status of the host over that of the tum or.