Abstract 184

Background: VLBW infants are dependent on parenteral nutrition(TPN) to prevent hypoglycemia and energy deficiency. However, diminished tolerance for parenteral glucose may provoke hyperglycemia. Thus, information on the gluconeogenic substrate role of amino acids and lipids is crucial to optimize the composition of TPN.

Aim: Estimate gluconeogenesis in VLBW infants receiving TPN with or without amino acids added, while the glucose supply is reduced to prevent hyperglycemia.

Subjects: 12 infants, 27±0.3(mean±SE) gestational wks, 1058±35 g birth weight were studied over 8 hrs on day 4.5±0.2 of life. 6 infants (AA-) received glucose 3 and lipids 1.6 mg/kg min; 6 infants (AA+) received glucose 3, lipids 1.6 and amino acids 2.3 mg/kg min.

Methods: Gluconeogenesis was measured by mass isotopomer distribution analysis using [2-13C]glycerol and, glucose Ra and leucine Ra with [U-13C]glucose and [1-13C]leucine.

Results: In the AA- and AA+ groups respectively, blood glucose=4.6±0.6 and 2.9±0.1 mM, glucose Ra=33.4±2.4 and 29.3±1.9 µmol/kg min, glucose production=17.0±2.4 and 11.3±1.8 µmol/kg min, leucine Ra=196±23 and 374±44µmol/kg h (p<0.0001), leucine from protein breakdown=196±23 and 229±45 µmol/kg h, gluconeogenic rate=7.4±0.7 and 7.7±0.8 µmol/kg min, representing 22±2 and 26±2 % of plasma glucose appearance rate.

Conclusion: Removal of amino acids from TPN does not compromise gluconeogenesis or increase protein breakdown.