• Demidmaa Tuvdendorj, David L Chinkes, Xiao-Jun Zhang, Oscar E Suman, Asle Aarsland, Arny Ferrando, Gabriela A Kulp, Marc G Jeschke, Robert R Wolfe, and David N Herndon.
• Department of Surgery, University of Texas Medical Branch, Galveston, TX 77555-1220, USA.
• Surgery. 2011 May 1; 149 (5): 645-53.

BackgroundWe recently showed that mechanisms of protein turnover in skeletal muscle are unresponsive to amino acid (AA) infusion in severely burned pediatric patients at 6 months postinjury. In the current study, we evaluated whether oxandrolone treatment affects mechanisms of protein turnover in skeletal muscle and whole-body protein breakdown in pediatric burn patients 6 months postinjury.MethodsAt the time of admission, patients were randomized to control or oxandrolone treatments. The treatment regimens were continued until 6 months postinjury, at which time patients (n = 26) underwent study with a stable isotope tracer infusion to measure muscle and whole-body protein turnover.ResultsProtein kinetics in leg muscle were expressed in nmol/min per 100 mL leg volume (mean ± SE). During AA infusion, rates of protein synthesis in leg muscle were increased (P < .05) in both groups (basal vs AA: control, 51 ± 8 vs 86 ± 21; oxandrolone, 56 ± 7 vs 96 ± 12). In the control group, there was also a simultaneous increase in breakdown (basal vs AA: 65 ± 10 vs 89 ± 25), which resulted in no change in the net balance of leg muscle protein (basal vs AA: -15 ± 4 vs -2 ± 10). In the oxandrolone group, protein breakdown did not change (basal vs AA: 80 ± 12 vs 77 ± 9), leading to increased net balance (basal vs AA: -24 ± 7 vs 19 ± 7; P < .05). Protein breakdown at the whole-body level was not different between the groups.ConclusionLong-term oxandrolone treatment increased net deposition of leg muscle protein during AA infusion by attenuating protein breakdown, but did not affect whole-body protein breakdown.Copyright © 2011 Mosby, Inc. All rights reserved.

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