Combined effects of hyperaminoacidemia and oxandrolone on skeletal muscle protein synthesis.
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.
Sheffield-Moore
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Department of Surgery, University of Texas Medical Branch, Galveston 77550, USA. melmoore@utmb.edu
Wolfe
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Gore
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Wolf
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Ferrer
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Ferrando
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D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage / Q000097:blood* / Q000378:metabolism; D045930:Anabolic Agents / Q000494:pharmacology*; D005263:Femoral Artery; D005268:Femoral Vein; D006801:Humans; D007700:Kinetics; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D010074:Oxandrolone / Q000494:pharmacology*; D010649:Phenylalanine / Q000378:metabolism
D000596:Amino Acids; D045930:Anabolic Agents; D009124:Muscle Proteins; D010649:Phenylalanine; D010074:Oxandrolone