title: Insulin mediates the linkage acceleration of muscle protein synthesis, thermogenesis, and heat storage by amino acids.
abstract: 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.
authors.affiliation: Research and Development Center, New Business and Development Department, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima 772-8601, Japan. yamaokih@otsukakj.co.jp
authors.forename: Ippei
authors.initials: I
authors.lastname: Yamaoka
authors.forename: Masako
authors.initials: M
authors.lastname: Doi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kawano
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Nakayama
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Kanae
authors.initials: K
authors.lastname: Oba
authors.forename: Kunio
authors.initials: K
authors.lastname: Sugahara
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Yoshizawa
mesh_terms: 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
chemical_list: D000596:Amino Acids; D007328:Insulin; D009124:Muscle Proteins; D013004:Somatostatin