Effect of short-term prednisone use on blood flow, muscle protein metabolism, and function.
Glucocorticoids can cause muscle atrophy, but the effect on muscle protein metabolism in humans has not been adequately studied to know whether protein synthesis, breakdown, or both are altered. We tested the effect of 6 d of oral prednisone (Pred, 0.5 mg/kg.d) on muscle protein metabolism and function. Six healthy subjects (three men/three women, 22-41 yr) completed two trials (randomized, double-blind, cross-over) with Pred and placebo. Fasting glucose, insulin, IGF-I, and glucagon were higher on Pred vs. placebo, whereas IGF-II and IGF binding protein-1 and -2 were lower. Whole-body amino acid fluxes, blood urea nitrogen, and urinary nitrogen loss were not statistically different between trials. Leg blood flow was 25% lower on Pred leading to 15-30% lower amino acid flux among the artery, vein, and muscle. However, amino acid net balance and rates of protein synthesis and breakdown were unchanged, as were synthesis rates of total mixed, mitochondrial, sarcoplasmic, and myosin heavy chain muscle proteins. Muscle mitochondrial function, muscle strength, and resting energy expenditure were also unchanged. These results demonstrate that a short-term moderate dose of prednisone affects glucose metabolism but has no effect on whole-body or leg muscle protein metabolism or muscle function.
Short
Kevin R
KR
Endocrinology Research Unit, Mayo Clinic School of Medicine, Rochester, Minnesota 55905, USA.
Nygren
Jonas
J
Bigelow
Maureen L
ML
Nair
K Sreekumaran
KS
D000284:Administration, Oral; D000328:Adult; D002153:Calorimetry, Indirect; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004734:Energy Metabolism; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000494:pharmacology; D006728:Hormones / Q000097:blood; D006801:Humans; D007700:Kinetics; D007866:Leg / Q000098:blood supply*; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism / Q000502:physiology*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D011241:Prednisone / Q000008:administration & dosage* / Q000494:pharmacology; D012039:Regional Blood Flow / Q000187:drug effects
D005938:Glucocorticoids; D006728:Hormones; D009124:Muscle Proteins; D011241:Prednisone