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Aging increases resting oxygen consumption in type‐II skeletal muscle
Author(s) -
Villarin Jason J,
Conley Kevin E,
Kushmerick Martin J,
Marcinek David J
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.954.10
Subject(s) - skeletal muscle , endocrinology , medicine , chemistry , oxygen , soleus muscle , oxidative phosphorylation , respiration , metabolism , reactive oxygen species , oxidative stress , mitochondrion , extensor digitorum longus muscle , sarcopenia , biology , biochemistry , anatomy , organic chemistry
Aging affects skeletal muscle metabolic function. Other studies have shown greater generation of reactive oxygen species and the resulting oxidative damage in Type‐II muscle fibers. We tested whether the greater oxidative stress results in a greater effect of age on metabolism in type II muscle. We compared oxidative metabolism in soleus muscle (SOL, primarily type I fibers) and extensor digitorum longus muscle (EDL, primarily type II fibers) of the C57BL/6 mouse in two age groups, 7‐9 months old (adult) and 27‐29 months old (aged). Saponin‐permeabilized muscles were measured with high‐resolution respirometry under ADP‐limiting (state 4) and activated (state 3) conditions. We found no difference in resting oxygen consumption (state 4) between SOL and EDL in adult muscle when normalized to wet weight. Aged muscle showed an elevation in resting oxygen consumption in EDL (62%, p<0.05), but not in soleus. Stimulated state‐3 respiration was higher in SOL, however there was no effect of age. These results suggest there is increased proton leak in the mitochondria during state‐4 metabolism in the predominantly type‐II EDL muscle with aging. Supported by NIH F32‐ AG029052 , RO1‐AG028455.