Inhibition of protein breakdown by glutamine in perfused rat skeletal muscle

FEBS Lett. 1988 Sep 12;237(1-2):133-6. doi: 10.1016/0014-5793(88)80186-8.


We have assessed the effects of glutamine (Gln) availability on protein breakdown in perfused rat hindlimb by measuring net phenylalanine (Phe) production (an index of protein balance), the dilution of [15N]Phe labelling (an index of mixed protein breakdown) and rate of production of 3-methylhistidine (3-MeH) (an index of myofibrillar breakdown). 15 mM Gln significantly inhibited net protein loss and protein breakdown compared to rates obtained in its absence (net protein loss, 200 +/- 230 vs 2080 +/- 200 nmol Phe/hindlimb per h; protein breakdown, 4566 +/- 480 vs 1614 +/- 180 nmol Phe/hindlimb per h; both p less than 0.01). Insulin (100 microU/ml) inhibited protein breakdown but less than Gln. The effects on protein breakdown of Gln and insulin together were not additive, suggesting a common mode of action. Production of 3-MeH (mean 20.3 +/- 2.8 nmol/hindlimb per h) was unaffected by Gln or insulin. Gln appears to inhibit protein breakdown of soluble rather than myofibrillar protein in muscle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Female
  • Glutamine / pharmacology*
  • Hindlimb
  • Kinetics
  • Muscles / drug effects
  • Muscles / metabolism*
  • Perfusion
  • Phenylalanine / analysis
  • Proteins / metabolism*
  • Rats
  • Rats, Inbred Strains
  • Reference Values


  • Proteins
  • Glutamine
  • Phenylalanine