Aminoacyl-tRNA enrichment after a flood of labeled phenylalanine: Insulin effect on muscle protein synthesis

Giuseppe Caso, G. Charles Ford, K Sreekumaran Nair, Peter J. Garlick, Margaret A. McNurlan

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Muscle protein synthesis in dogs measured by flooding with L-[2H5] phenylalanine (70 mg/kg) was significantly stimulated by infusion of insulin with amino acids. The stimulation of muscle protein synthesis was similar when calculated from the enrichment of phenylalanyl-tRNA (61 ± 10%, P < 0.001), plasma phenylalanine (61 ± 10%, P < 0.001), or tissue fluid phenylalanine (54 ± 10%, P < 0.001). The time course for changes in enrichment of L-[2H5]phenylalanine throughout the flooding period was determined for plasma, tissue fluid, and phenylalanyl-tRNA in the basal state and during the infusion of insulin with amino acids. Enrichments of plasma free phenylalanine and phenylalanyl-tRNA were equalized between 20 and 45 min, although the enrichment of phenylalanyl-tRNA was lower at early time points. Rates of muscle protein synthesis obtained with the flooding method and calculated from plasma phenylalanine enrichment were comparable to those calculated from phenylalanyl-tRNA and also to those obtained previously with a continuous infusion of phenylalanine with phenylalanyl-tRNA as precursor. This study confirms that, with a bolus injection of labeled phenylalanine, the enrichment of aminoacyl-tRNA, the true precursor pool for protein synthesis, can be assessed from more readily sampled plasma phenylalanine.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume282
Issue number5 45-5
StatePublished - 2002

Fingerprint

Muscle Proteins
Transfer RNA
Phenylalanine
Insulin
Plasmas
RNA Precursors
Tissue
Amino Acids
Fluids
Dogs
Injections

Keywords

  • Amino acids
  • Dog
  • Flooding technique
  • Ketoisocaproic acid
  • L-[H]phenylalanine
  • Stable isotopes

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Biochemistry

Cite this

Aminoacyl-tRNA enrichment after a flood of labeled phenylalanine : Insulin effect on muscle protein synthesis. / Caso, Giuseppe; Charles Ford, G.; Nair, K Sreekumaran; Garlick, Peter J.; McNurlan, Margaret A.

In: American Journal of Physiology - Endocrinology and Metabolism, Vol. 282, No. 5 45-5, 2002.

Research output: Contribution to journalArticle

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