title: The effects of intraperitoneal clenbuterol injection on protein degradation and myostatin expression differ between the sartorius and pectoral muscles of neonatal chicks.
abstract: The purpose of this study was to investigate the effects of injection of the β2-adrenergic receptor agonist clenbuterol on the skeletal muscles of neonatal chicks (Gallus gallus domesticus). One-day-old chicks were randomly divided into four groups and given a single intraperitoneal injection of clenbuterol (0.01, 0.1, or 1mg/kg) or phosphate-buffered saline. Twenty-four hours after the injection, the sartorius muscles (which consist of both slow- and fast-twitch fibers) of chicks that received 0.01 or 0.1mg/kg clenbuterol were significantly heavier than those of controls, while there were no between-group differences in the weight of the pectoral muscles, which consist of only fast-twitch fibers. Muscle free N(t)-methylhistidine, regarded as an index of myofibrillar proteolysis, was decreased in the sartorius muscle of the clenbuterol-injected chicks, while it was not affected in the pectoral muscles. In the sartorius muscle of the clenbuterol-injected chicks, myostatin and atrogin-1/MAFbx mRNA expressions were decreased, while insulin-like growth factor-I was unaffected. These observations suggested, in 1-day-old chicks, clenbuterol might increase mass of the sartorius muscle by decreasing myostatin gene expression and protein degradation.
authors.affiliation: Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan. Electronic address: ijiri@chem.agri.kagoshima-u.ac.jp.
authors.forename: Daichi
authors.initials: D
authors.lastname: Ijiri
authors.affiliation: Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Kanae
authors.initials: K
authors.lastname: Ishitani
authors.affiliation: Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Saki
authors.initials: S
authors.lastname: Shimamoto
authors.affiliation: Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Ishimaru
authors.affiliation: Department of Biochemical Science and Technology, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ohtsuka
mesh_terms: D000318:Adrenergic beta-Agonists / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002645:Chickens / Q000378:metabolism*; D002976:Clenbuterol / Q000008:administration & dosage* / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D008297:Male; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D055435:Myostatin / Q000235:genetics / Q000378:metabolism*; D010369:Pectoralis Muscles / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D059748:Proteolysis / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000318:Adrenergic beta-Agonists; D009124:Muscle Proteins; D055435:Myostatin; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D002976:Clenbuterol
keywords: Gallus gallus domesticus; Muscle growth; Myofibrillar proteolysis; β(2)-Adrenergic receptor