Combined effects of hyperaminoacidemia and oxandrolone on skeletal muscle protein synthesis

Am J Physiol Endocrinol Metab. 2000 Feb;278(2):E273-9. doi: 10.1152/ajpendo.2000.278.2.E273.


We investigated whether the normal anabolic effects of acute hyperaminoacidemia were maintained after 5 days of oxandrolone (Oxandrin, Ox)-induced anabolism. Five healthy men [22 +/- 3 (SD) yr] were studied before and after 5 days of oral Ox (15 mg/day). In each study, a 5-h basal period was followed by a 3-h primed-continuous infusion of a commercial amino acid mixture (10% Travasol). Stable isotopic data from blood and muscle sampling were analyzed using a three-compartment model to calculate muscle protein synthesis and breakdown. Model-derived muscle protein synthesis increased after amino acid infusion in both the control [basal control (BC) vs. control + amino acids (C+AA); P < 0.001] and Ox study [basal Ox (BOx) vs. Ox + amino acids (Ox+AA); P < 0.01], whereas protein breakdown was unchanged. Fractional synthetic rates of muscle protein increased 94% (BC vs. C+AA; P = 0.01) and 53% (BOx vs. Ox+AA; P < 0.01), respectively. We conclude that the normal anabolic effects of acute hyperaminoacidemia are maintained in skeletal muscle undergoing oxandrolone-induced anabolism.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Amino Acids / administration & dosage
  • Amino Acids / blood*
  • Amino Acids / metabolism
  • Anabolic Agents / pharmacology*
  • Femoral Artery
  • Femoral Vein
  • Humans
  • Kinetics
  • Male
  • Muscle Proteins / biosynthesis*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism*
  • Oxandrolone / pharmacology*
  • Phenylalanine / metabolism


  • Amino Acids
  • Anabolic Agents
  • Muscle Proteins
  • Phenylalanine
  • Oxandrolone