Effects of a parenteral nutrition regimen containing dicarboxylic amino acids on plasma, erythrocyte, and urinary amino acid concentrations of young infants.

Plasma, erythrocyte, and urinary amino acid concentrations were measured in young infants infused with a solution containing glutamate and aspartate. Eight infants (1.2 to 2.8 kg) were fed parenterally (80 kcal/kg/day) with two regimens containing dextrose (15 g/kg/day), amino acids (2 g/kg/day), and lipid (2 g/kg/day) for successive 3-day periods in a cross-over design. The regimens differed only in the amino acid source. One regimen (I) provided glutamate (1.5 mmol/kg/day) and aspartate (1.0 mmol/kg/day), while the other regimen (II) did not. The mean (+/- SD) plasma glutamate concentration was slightly, but significantly higher (89.9 +/- 28.5 microM) during infusion of regimen I than regimen II (66.5 +/- 19.8 microM), but values did not differ significantly from values observed in normal, orally fed premature infants (107 +/- 36 microM). No significant differences were noted in either plasma or erythrocyte aspartate concentrations, or in erythrocyte glutamate concentration. Since plasma and erythrocyte levels of dicarboxylic amino acids remained within the normal range, the data indicate no hazard to young infants from infusion of dicarboxylic amino acids at this level.