Skeletal muscle adaptations to testosterone and resistance training in men with COPD.
We recently reported increased leg lean mass and strength in men with chronic obstructive pulmonary disease (COPD) receiving 10 wk of testosterone (T) and leg resistance training (R) (Casaburi R, Bhasin S, Cosentino L, Porszasz J, Somfay A, Lewis M, Fournier M, Storer T. Am J Respir Crit Care Med 170: 870-878, 2004). The present study evaluates the role of muscle IGF and related factors as potential mechanisms for our findings, using quadriceps muscle biopsies from the same cohort. Patient groups were 1) weekly placebo (P) injections + no R; 2) P and R; 3) weekly injections of T + no R; and 4) T + R (TR). Muscle fibers were classified histochemically, and their cross-sectional areas (CSAs) and fiber density (number of fibers per unit area) were determined. Gene transcripts were determined by real-time PCR and protein expression by RIA. While no significant changes in fiber CSAs were noted across groups, increased trends were observed after 10 wk, and significant decrements in muscle fiber density were noted in all treated groups. A global increase in all myosin heavy chain (MyHC) mRNA isoforms was observed in TR patients. Muscle IGF-IEa and IGF-IEc mRNAs were significantly increased with TR group. Muscle IGF-I protein was increased in all intervention groups (greatest in TR). While TR IGF-II mRNA was increased, protein levels were unaltered. IGF binding protein-4 mRNA was increased with TR. Myogenin mRNA was increased in both T groups, while MyoD and myostatin were unchanged. Muscle atrophy F-box mRNA tended to increase with TR. Our data suggest that the combined interventions produced an enhanced local anabolic milieu driven in large part by the muscle IGF system, despite potentially negative biochemical influences present in COPD patients.
Lewis
Michael I
MI
Division of Pulmonary and Critical Care Medicine, The Burns and Allen Research Institute at Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA. michael.lewis@cshs.org
Fournier
Mario
M
Storer
Thomas W
TW
Bhasin
Shalender
S
Porszasz
Janos
J
Ren
Song-Guang
SG
Da
Xiaoyu
X
Casaburi
Richard
R
D000368:Aged; D000369:Aged, 80 and over; D005081:Exercise Therapy; D015870:Gene Expression / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000235:genetics / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000378:metabolism* / Q000473:pathology; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000503:physiopathology / Q000534:rehabilitation*; D012333:RNA, Messenger / Q000378:metabolism; D044843:SKP Cullin F-Box Protein Ligases / Q000235:genetics / Q000378:metabolism; D013739:Testosterone / Q000097:blood / Q000627:therapeutic use*; D016896:Treatment Outcome
D018974:Insulin-Like Growth Factor Binding Protein 4; D009124:Muscle Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; C440907:FBXO32 protein, human; D044843:SKP Cullin F-Box Protein Ligases; D018995:Myosin Heavy Chains