Effects of feeding on protein turnover in healthy children and in children with cystic fibrosis

C. Lawrence Kien, William B. Zipf, Craig A. Horswill, Scott C. Denne, Karen S. McCoy, Thomas M. O'Dorisio

Research output: Contribution to journalArticle

30 Scopus citations


We hypothesized that there is less suppression of whole-body protein breakdown with feeding in patients with cystic fibrosis (CF) who exhibit decreased insulin secretion after a single meal. Using [1-13C]leucine, we measured rate of monoxidative leucine disappearance (whole-body protein synthesis) and protein breakdown in nine CF patient (6-11 y of age) and five healthy control subject (8-10 y of age) during feeding and fasting. In the CF patients, synthesis and breakdown (x̄ ± SD) were 172 ± 61 and 157 ± 67 μmol · kg-1 · h-1 during feeding and 140 ± 24 and 178 ± 26 μmol · kg-1 · h-1 during fasting. The respective control value were 129 ± 27 and 114 ± 20 μmol · kg-1 · h-1 during feeding and 136 ± 13 and 173 ± 18 μmol · kg-1 · h-1 during fasting. Leucine balance was nearly identical in the two groups. By analysis of variance, there was a significant effect of feeding on protein breakdown but no difference between the group. However, when each group was analyzed separately, feeding resulted in a 34% decrease in breakdown in the control subjects (P = 0.001) and a 23% increase in synthesis in the CF group (P = 0.058). Plasma insulin concentrations did not differ in the two groups. Thus, feeding may effect protein turnover differently in children with CF than in control children independently of plasma insulin concentration.

Original languageEnglish (US)
Pages (from-to)608-614
Number of pages7
JournalAmerican Journal of Clinical Nutrition
Issue number4
StatePublished - Oct 1996


  • Cystic fibrosis
  • insulin
  • leucine
  • protein breakdown
  • protein degradation
  • protein synthesis

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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