Year, Volume, Issue, Page(s):11, 149, 5, 645-653
Study evaluated whether oxandrolone treatment affects mechanisms of protein turnover in skeletal muscle in response to amino acid (AA) infusion and on whole-body protein breakdown in pediatric burn patients 6 months postinjury. At the time of admission, patients were randomized to control or oxandrolone treatments. Clinically, oxandrolone has been used successfully to treat muscle wasting and conditions of growth disorders. The treatment regimens were continued until 6 months postinjury, at which time 26 patients underwent study with a stable isotope tracer infusion to measure muscle and whole-body protein turnover. Protein kinetics in leg muscle were expressed in nanomoles per minute per 100 milliliters of leg volume. During AA infusion, rates of protein synthesis in leg muscle were increased in both groups (basal versus AA: control, 51 versus 86; oxandrolone, 56 versus 96). In the control group, there was also a simultaneous increase in breakdown (basal versuss AA: 65 versus 89), which resulted in no change in the net balance of leg muscle protein (basal versus AA: -15 versus -2). In the oxandrolone group, protein breakdown did not change (basal versus AA: 80 versus 77), leading to increased net balance (basal versus AA: -24 versus 19). Protein breakdown at the whole-body level was not different between the groups. This study shows that long-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.