Document Detail

Amino acids suppress proteolysis independent of insulin throughout the neonatal period.
MedLine Citation:
PMID:  9142879     Owner:  NLM     Status:  MEDLINE    
To determine how increased amino acid availability alters rates of whole body proteolysis and the irreversible catabolism of the essential amino acids leucine and phenylalanine throughout the neonatal period, leucine and phenylalanine kinetics were measured under basal conditions and in response to intravenous amino acids in two separate groups of healthy, full-term newborns (at 3 days and 3 wk of age). The endogenous rates of appearance of leucine and phenylalanine (reflecting proteolysis) were suppressed equally in both groups and in a dose-dependent fashion (by approximately 10% with 1.2 g x kg(-1) x day(-1) and by approximately 20% with 2.4 g x kg(-1) x day(-1)) in response to intravenous amino acid delivery. Insulin concentrations remained unchanged from basal values during amino acid administration. The irreversible catabolism of leucine and phenylalanine increased in a stepwise fashion in response to intravenous amino acids; again, no differences were observed between the two groups. This study clearly demonstrates that the capacity to acutely increase rates of leucine oxidation and phenylalanine hydroxylation is fully present early in the neonatal period in normal newborns. Furthermore, these data suggest that amino acid availability is a primary regulator of proteolysis in normal newborns throughout the neonatal period.
B B Poindexter; C A Karn; J A Ahlrichs; J Wang; C A Leitch; E A Liechty; S C Denne
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  272     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1997 Apr 
Date Detail:
Created Date:  1997-06-06     Completed Date:  1997-06-06     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  E592-9     Citation Subset:  IM    
Department of Pediatrics, Indiana University School of Medicine, Indianapolis 46202, USA.
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MeSH Terms
Aging / blood
Amino Acids / blood,  pharmacology*
Blood Glucose / analysis
Infant, Newborn / blood*
Infusions, Intravenous
Insulin / blood,  physiology*
Leucine / blood
Osmolar Concentration
Peptide Hydrolases / metabolism*
Phenylalanine / blood
Protease Inhibitors / pharmacology*
Tyrosine / blood
Grant Support
Reg. No./Substance:
0/Amino Acids; 0/Blood Glucose; 0/Protease Inhibitors; 11061-68-0/Insulin; 55520-40-6/Tyrosine; 61-90-5/Leucine; 63-91-2/Phenylalanine; EC 3.4.-/Peptide Hydrolases

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