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Acute exercise increases serum retinol binding protein 4 concentrations
Author(s) -
Brandauer Josef,
Graham Timothy E.,
Röckl Katja S. C.,
Wason Christopher,
Goodyear Laurie J.,
Kahn Barbara B.
Publication year - 2007
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.21.6.a928-c
Subject(s) - retinol binding protein 4 , medicine , endocrinology , adipose tissue , insulin resistance , homeostasis , chemistry , insulin , adipokine
Serum retinol binding protein (sRBP4) levels are increased in insulin resistance and type 2 diabetes. RBP4 enhances hepatic glucose output (HGO) in cultured hepatocytes. During acute exercise, increased HGO balances a rise in muscle glucose uptake. We hypothesized that treadmill running in rats might increase sRBP4 concentrations. RBP4 was measured in sera of female SD rats in the sedentary state, after 60 minutes of exercise, or after 60 minutes of rest following exercise. RBP4 mRNA was detected in muscle, albeit at lower levels than in liver or visceral adipose tissue. Relative to the sedentary state, exercise increased sRBP4 concentrations (mean ± SEM, 100 ± 9.7 vs. 130 ± 9.2 AU; p < 0.05) and stimulated an ~4‐fold increase of RBP4 mRNA in gastrocnemius muscle which declined toward sedentary levels 60 min after exercise cessation. RBP4 mRNA in liver and adipose tissue remained unchanged. The surprising finding that RBP4 mRNA is expressed in muscle and selectively induced in muscle by exercise suggests the possibility that exercise may stimulate synthesis and secretion of RBP4 from muscle. Therefore, RBP4 may be a novel muscle‐secreted signal contributing to fuel homeostasis during exercise. SUPPORT: NIH T32 DK07260‐29, DK068626 , 43051, 69624