Insulin mediates the linkage acceleration of muscle protein synthesis, thermogenesis, and heat storage by amino acids.
Amino acid (AA) administration can stimulate heat accumulation in the body, as especially found under anesthetic conditions. To test our hypothesis that marked rise in plasma insulin concentrations following AA administration plays an important role in the heat storage, we intravenously administered either a balanced AA mixture or saline over 3 h, both with and without a primed-constant infusion of somatostatin in propofol-anesthetized rats. Rats on AA but lacking marked rise in plasma insulin by somatostatin treatment failed to show: attenuation of fall in core body temperature; partial increases in oxygen consumption; and stimulated muscle protein synthesis. Furthermore, the AA's stimulatory effects on phosphorylation of mTOR, 4E-BP1, and S6K1 were partially blocked by somatostatin. Our findings strongly suggest that the marked rise in insulin following AA administration promote translation initiation activities and stimulate muscle protein synthesis, which facilitates heat accumulation in the body.
Yamaoka
Ippei
I
Research and Development Center, New Business and Development Department, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima 772-8601, Japan. yamaokih@otsukakj.co.jp
Doi
Masako
M
Kawano
Yuichi
Y
Nakayama
Mitsuo
M
Watanabe
Yosuke
Y
Oba
Kanae
K
Sugahara
Kunio
K
Yoshizawa
Fumiaki
F
D000596:Amino Acids / Q000008:administration & dosage*; D000818:Animals; D007328:Insulin / Q000097:blood*; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D010101:Oxygen Consumption; D010442:Peptide Chain Initiation, Translational / Q000187:drug effects*; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013004:Somatostatin / Q000008:administration & dosage; D022722:Thermogenesis
D000596:Amino Acids; D007328:Insulin; D009124:Muscle Proteins; D013004:Somatostatin