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Influence of age on leptin induced skeletal muscle signalling
Author(s) -
GuadalupeGrau A.,
Larsen S.,
Guerra B.,
Calbet J. A. L.,
Dela F.,
Helge J. W.
Publication year - 2014
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.12273
Subject(s) - medicine , endocrinology , leptin , skeletal muscle , socs3 , leptin receptor , insulin receptor , ampk , stat protein , stat3 , biology , chemistry , protein kinase a , insulin , kinase , phosphorylation , insulin resistance , obesity , microbiology and biotechnology , cancer , suppressor
Aim Age associated fat mass accumulation could be because of dysregulation of leptin signalling in skeletal muscle. Thus, we investigated total protein expression and phosphorylation levels of the long isoform of the leptin receptor ( OB ‐Rb), and leptin signalling through janus kinase 2 ( JAK 2)/signal transducer and activator of transcription 3 ( STAT 3), insulin receptor substrate 1 ( IRS ‐1), AMP ‐activated protein kinase ( AMPK ) and acetyl‐coenzyme A carboxylase ( ACC ), combined with the leptin signalling inhibitors suppressor of cytokine signalling 3 ( SOCS 3) and protein tyrosine phosphatase 1B ( PTP 1B) in human skeletal muscle of different age. Methods Vastus lateralis muscle biopsies were obtained from 39 men matched for BMI < 30 kg m −2 and separated into three groups: 13 young (Y, 24 ± 4 years); 14 middle aged ( MA , 44 ± 5 years) and 12 aged (A, 58 ± 8 years) subjects. Results Whole body fat percentage and plasma leptin were higher ( P < 0.05), whereas lean mass, plasma free testosterone and total testosterone were lower ( P < 0.05) in A compared to Y. Skeletal muscle OB‐Rb (170 KDa) protein expression and pT yr 1141 ‐OB‐R170 were comparable between groups, whereas pT yr 985 ‐OB‐R170 was lower in A compared to Y ( P < 0.05). pSTAT 3 levels tended ( P = 0.09) to be lower (50%) in A compared to Y. In A, muscle PTP1B was greater and IRS‐1 lower than Y and MA respectively ( P < 0.05). PTyr 612 ‐IRS‐1 tended to be lower in A than in Y ( P = 0.09). Suppressor of cytokine signalling 3 (SOCS3) protein expression, pJAK 2, pS er 1101 ‐IRS‐1, pAMPK α and pACC β were similar between groups. Conclusion Age is associated with dysregulation of the leptin signalling and increased PTP 1B protein expression in skeletal muscle.