Effects of an amino acid dialysate on leucine metabolism in continuous ambulatory peritoneal dialysis patients

Background. Protein-energy malnutrition is frequent in continuous ambulator y peritoneal dialysis (CAPD) patients. The use of amino acids in the dialys ate could improve the protein balance, especially if associated to a concom itant energy intake. Methods. A 1.1% amino acid solution for peritoneal dialysis was administere d to CAPD patients over 30 minutes during concomitant absorption of 600 mi water (control study) or of a 600 kcal meal/600 mi. Leucine metabolism was studied using the combination of intravenous [H-2(3)] and intraperitoneal [ C-13] leucine. Results. The rate of leucine appearance was stimulated by 56 and 53% (contr ol and meal) at 45 minutes. The rates of leucine appearance and disappearan ce were lower from 180 to 300 minutes during the meal versus control study (P < 0.05). Proteolysis was unaffected during the control study and was inh ibited by 25% during the meal study (P < 0.05). During the Eve-hour cycle d ialysis with or without a meal, 80% of the leucine administered into the pe ritoneum was absorbed. Forty one percent was retained in the splanchnic bed . Forty-three percent was used for protein synthesis, and 16% was oxidized. Conclusions. This amino acids solution is efficaciously utilized for protei n synthesis in CAPD patients with no effect on protein breakdown. The conco mitant ingestion of a carbohydrate-lipid meal inhibits protein breakdown an d reinforces a positive effect of the amino acids solution on protein balan ce.