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Aerobic exercise + weight loss decreases skeletal muscle myostatin expression and improves insulin sensitivity in older adults
Author(s) -
Ryan A.S.,
Li G.,
Blumenthal J.B.,
Ortmeyer H.K.
Publication year - 2013
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1002/oby.20216
Subject(s) - myostatin , endocrinology , medicine , myogenin , myod , insulin , vo2 max , skeletal muscle , aerobic exercise , chemistry , heart rate , myogenesis , blood pressure
Objective To determine whether aerobic exercise training + weight loss (AEX + WL) would affect the expression of myostatin and its relationship with insulin sensitivity in a longitudinal, clinical intervention study. Design and Methods Thirty‐three obese sedentary postmenopausal women and men ( n = 17 and 16, age: 61 ± 1 years, body mass index: 31 ± 1 kg/m 2 , VO 2 max: 21.9 ± 1.0 mL/kg/min, X ± Standard error of the mean (SEM)) completed 6 months of 3 days/week AEX + WL. During an 80 mU m −2 min −1 hyperinsulinemic‐euglycemic clamp, we measured glucose utilization ( M ), myostatin, myogenin, and MyoD gene expression by real‐time RT‐PCR in vastus lateralis muscle at baseline and 2 h. Results Body weight (−8%) and fat mass (−17%) decreased after AEX + WL ( P < 0.001). Fat‐free mass (FFM) and mid‐thigh muscle area by computed tomography did not change but muscle attenuation increased ( P < 0.05). VO 2 max increased 14% ( P < 0.001). AEX + WL increased M by 18% ( P < 0.01). Myostatin gene expression decreased 19% after AEX + WL ( P < 0.05). Basal mRNA myostatin levels were negatively associated with M before the intervention ( r = −0.43, P < 0.05). Insulin infusion increased myoD and myogenin expression before and after AEX + WL (both P < 0.001) but basal levels did not change. The insulin effect on myostatin expression was associated with the change in M after AEX + WL ( r = 0.56, P < 0.005). Conclusions Exercise and weight loss results in a downregulation of myostatin mRNA and an improvement in insulin sensitivity in obese older men and women.