The Effect on the Nitrogen Balance of the Ratio Essential/Non-Essential Amino Acids in Intravenously Infused Solutions

After 4 days on a nitrogen-poor diet healthy adult volunteers were nourished only with nitrogen-free carbohydrates given by mouth and amino acid solu tions infused intravenously during 4 consecutive days. In all experiments about 5 g of amino acid nitrogen was administered intravenously on each of these 4 days. The composition of the amino acid solutions was varied so that the mutual ratios between the essentials were constant, as were the mutual ratios between the non-essentials, whereas the ratio essentials/non essentials differed. Five solutions were tested containing 0, 25, 30, 36, and 46 % of their nitrogen as essential amino acids. The nitrogen balance was considerably negative when only non-essential amino acids were administered and significantly less negative when the other solutions were infused. On the other hand, there was no significant difference between the nitrogen balances when the solutions contained 25, 30, 36, or 46 % essential nitrogen.