QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Papet, I. Articles by Arnal, M. Search for Related Content PubMed PubMed Citation Articles by Papet, I. Articles by Arnal, M.

Leucine Excess under Conditions of Low or Compensated Aminoacidemia does not Change Skeletal Muscle and Whole-Body Protein Synthesis in Suckling Lambs during the Postprandial Period

Laboratoire d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Centre de Recherches de Clermont-Ferrand Theix, 63122 Ceyrat, France

We determined the effect of a 4-h leucine infusion, leading to 15-fold elevated plasma leucine concentrations, on skeletal muscle and whole-body protein synthesis in suckling lambs during the postprandial period. The [³H]phenylalanine large dose method was validated and used to quantify the fractional rates of protein synthesis (K_S in %/d) at the end of the leucine infusion. In the first experiment leucine infusion lowered plasma amino acid concentrations but did not change the K_S, the capacity for protein synthesis (C_S, mg RNA/g protein) or the efficiency of translation [g protein synthesized/(d·g RNA)] in any muscles studied or the whole body. In the second experiment the leucine-induced decreases in plasma amino acid concentrations were compensated by the simultaneous infusion of substantial amounts of amino acids. Again leucine excess did not significantly change K_S, C_S and efficiency of protein synthesis. These results indicated that leucine excess in suckling lambs during the postprandial period lowered aminoacidemia without any change of the protein synthesis rates in skeletal muscles or the whole body.

KEY WORDS: • leucine • protein synthesis • muscle • isotope • lambs

¹ To whom correspondence should be addressed.

Manuscript received 2 December 1991. Revision accepted 17 July 1992.