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Amino acids do not suppress proteolysis in premature neonates

B B Poindexter1, C A Karn, C A Leitch

  • 1Section of Neonatal-Perinatal Medicine, Department of Pediatrics, Indiana University School of Medicine, 699 West Dr. RR208, Indianapolis, IN 46202, USA. bpoindex@iupui.edu

American Journal of Physiology. Endocrinology and Metabolism
|August 14, 2001
PubMed

Insights

Premature infants do not reduce protein breakdown with increased amino acids, unlike full-term infants. However, they can increase essential amino acid metabolism, crucial for meeting nutritional needs.

Area of Science:

  • Biochemistry
  • Neonatal Physiology
  • Nutritional Science

Background:

  • Premature neonates have unique metabolic needs and challenges.
  • Understanding amino acid metabolism is vital for optimizing nutrition in preterm infants.
  • Proteolysis and amino acid catabolism regulation may differ in premature infants.

Purpose of the Study:

  • To investigate if increased amino acid availability reduces proteolysis in premature neonates.
  • To assess the premature infant's capacity for essential amino acid catabolism (leucine oxidation, phenylalanine hydroxylation).
  • To determine if amino acids stimulate glucose production in premature neonates.

Main Methods:

  • Measured leucine and phenylalanine kinetics in premature infants (32 wk gestation) during the first week of life.
  • Administered graded infusions of intravenous amino acids (1.2 and 2.4 g.kg(-1).day(-1)).
  • Assessed endogenous rates of appearance (proteolysis), leucine oxidation, phenylalanine hydroxylation, and glucose production.

Main Results:

  • Amino acid infusion did not suppress proteolysis in premature infants, unlike in full-term neonates.
  • Leucine oxidation and phenylalanine hydroxylation increased stepwise with amino acid infusion.
  • Endogenous glucose production remained unchanged despite amino acid administration.

Conclusions:

  • Premature neonates exhibit a different response to amino acid availability regarding proteolysis compared to full-term infants.
  • Premature infants possess the capacity to increase essential amino acid catabolism, potentially vital for tyrosine synthesis.
  • Amino acids do not stimulate glucose production in premature neonates during the first week of life.

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