Effect of intravenous glucose and lipid on proteolysis and glucose production in normal newborns

S. C. Denne, C. A. Karn, J. Wang, E. A. Liechty

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35 Scopus citations


To determine whether nonprotein substrate can suppress proteolysis in normal newborns and to assess the effect of this substrate on glucose production, the rates of appearance (R(a)) of leucine (reflecting proteolysis) and glucose were measured in healthy 2-day-old full-term newborns during fasting, an intravenous glucose infusion (5.5 mg · kg-1 · min-1), an intravenous lipid infusion (2.5 mg · kg-1 · min-1), and a combined glucose plus lipid infusion (5.5 mg · kg-1 · min-1 glucose + 2.5 mg · kg-1 · min-1 lipid). Leucine R(a) was not reduced from fasting values during any of the substrate infusions. Intravenous lipid infusion alone neither suppressed nor increased glucose production. In contrast, glucose production was nearly completely suppressed (~ 90%) during intravenous infusions of glucose provided either alone or in combination with lipid; this suppression was achieved at glucose concentrations of ~ 90 mg/dl and insulin concentrations of ~6 μU/ml. Thus normal newborns respond to intravenous glucose with sustained nearly complete suppression of glucose production, even at moderate levels of glycemia and at low insulin concentrations; however, nonprotein substrate infusion does not result in suppression of proteolysis. It remains unclear to what extent any potential regulator can suppress proteolysis in this population.

Original languageEnglish (US)
Pages (from-to)E361-E367
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Issue number2 32-2
StatePublished - 1995


  • leucine
  • protein turnover
  • stable isotope tracers

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Physiology
  • Agricultural and Biological Sciences(all)

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