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Arginine supplementation induces myoblast fusion via augmentation of nitric oxide production
Author(s) -
Long Jodi Heather Dixon,
Soltow Quinlyn A,
Lira Vitor A,
Criswell David S
Publication year - 2006
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.20.4.a29-b
Subject(s) - nitric oxide , chemistry , arginine , nitric oxide synthase , endogeny , biochemistry , cell fusion , myocyte , microbiology and biotechnology , biology , endocrinology , cell , amino acid
The semi‐essential amino acid, L‐arginine (L‐Arg), is the substrate for endogenous synthesis of nitric oxide, a molecule that is involved in myoblast proliferation and fusion. Therefore, we examined L‐Arg supplementation in differentiating mouse myoblasts and tested the hypothesis that L‐Arg exerts direct effects on cell fusion via augmentation of endogenous nitric oxide production. C2C12 myoblasts were cultured and maintained in growth medium (DMEM supplemented with 10% fetal bovine serum) in a humidified incubator at 37°C, 5% CO 2 until 80% confluency was reached, then switched to differentiation media (DMEM supplemented with 10% horse serum) containing one of the following treatments for 120h: 1mM L‐Arg, 100mM N‐nitro‐L‐arginine methyl ester (L‐NAME), L‐Arg + L‐NAME, 10mM L‐Lysine, or no supplement (Control). Cultures (n=6/treatment) were fixed and stained with hematoxylin and eosin (H&E) for microphotometric image analysis of myotube area, myotube density, nuclear density, and fusion index. Endogenous production of nitric oxide during the treatment period, assessed by measurement of nitrite/nitrate in culture media, peaked between 24 and 48h. L‐Arg amplified nitric oxide production between 12 and 24h and increased myotube size, density, and nuclear fusion index. These L‐Arg effects were prevented by the NOS inhibitor, L‐NAME. Further, L‐Lysine, a competitive inhibitor of L‐Arg uptake, repressed nitric oxide production and reduced myotube density and fusion index. In summary, L‐Arg augments myotube formation by increasing nitric oxide production in a process limited by cellular L‐Arg uptake.