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Energy‐induced changes in skeletal muscle protein synthesis and molecular signaling in physically active adults
Author(s) -
Pasiakos Stefan M,
Vislocky Lisa M,
Carbone John W,
Freake Hedley C,
Anderson Jeffrey M,
Ferrando Arny A,
Wolfe Robert R,
Rodriguez Nancy R
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.541.2
Subject(s) - skeletal muscle , calorie , endocrinology , resting energy expenditure , medicine , energy balance , chemistry , protein kinase b , phosphorylation , energy metabolism , biology , biochemistry , ecology
To date, no studies have characterized how energy deprivation influences skeletal muscle protein utilization. PURPOSE This investigation characterized the effect of an acute energy deficit on mixed muscle protein synthesis (MPS) and associated intracellular signaling proteins (ISPs) in physically active adults. METHODS Eleven men and seven women participated in a 20‐d, two‐phase diet intervention study: weight maintenance, WM; and energy deficient, ~80% of estimated energy requirements, ED. Dietary protein (1.5 g·kg −1· d −1 ) and fat (~30% of total calories) were constant for WM and ED. MPS and ISPs were measured on day 10 of both interventions using a primed, constant infusion of [ 2 H 5 ]‐phenylalanine and Western blotting techniques, respectively. Resting energy expenditure (REE) was estimated using indirect calorimetry and nitrogen balance (NBAL) was determined. RESULTS Subjects lost ~1 kg body weight during ED ( P < 0.0001 ). REE or NBAL were not affected. MPS was reduced ~33% ( P < 0.05 ) for ED (0.056 ± 0.01 %/h) compared to WM (0.083 ± 0.007 %/h). Akt and 4E‐BP1 phosphorylation were lower ( P < 0.05 ) during ED compared to WM. CONCLUSION These findings show that MPS and associated synthetic ISPs are downregulated in response to an acute, moderate energy deficit in physically active adults and provide a basis for studies assessing the impact of prolonged energy restriction on skeletal muscle protein metabolism. Grant Funding Source National Cattlemen's Beef Association