Amino acids, glutamine, and protein metabolism in very low birth weight infants

Prabhu S. Parimi, Mark M. Kadrofske, Lourdes L. Gruca, Richard W. Hanson, Satish C. Kalhan

Research output: Contribution to journalArticle

Abstract

Glutamine has been proposed to be conditionally essential for premature infants, and the currently used parenteral nutrient mixtures do not contain glutamine. De novo glutamine synthesis (DGln) is linked to inflow of carbon into and out of the tricarboxylic acid (TCA) cycle. We hypothesized that a higher supply of parenteral amino acids by increasing the influx of amino acid carbon into the TCA cycle will enhance the rate of DGln. Very low birth weight infants were randomized to receive parenteral amino acids either 1.5 g/kg/d for 20 h followed by 3.0 g/kg/d for 5 h (AA1.5) or 3.0 g/kg/d for 20 h followed by 1.5 g/kg/d for 5 h (AA3.0). A third group of babies received amino acids 1.5 g/kg/d for 20 h followed by 3.0 g/kg/d for 20 h (AA-Ext). Glutamine and protein/nitrogen kinetics were examined using [5-15N]glutamine, [2H5]phenylalanine, [1-13C,15N] leucine, and [15N2]urea tracers. An acute increase in parenteral amino acid infusion for 5 h (AA1.5) resulted in decrease in rate of appearance (Ra) of phenylalanine and urea, but had no effect on glutamine Ra. Infusion of amino acids at 3.0 g/kg/d for 20 h resulted in increase in DGln, leucine transamination, and urea synthesis, but had no effect on Ra phenylalanine (AA-Ext). These data show an acute increase in parenteral amino acid-suppressed proteolysis, however, such an effect was not seen when amino acids were infused for 20 h and resulted in an increase in glutamine synthesis.

Original languageEnglish (US)
Pages (from-to)1259-1264
Number of pages6
JournalPediatric research
Volume58
Issue number6
DOIs
StatePublished - Dec 1 2005

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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