title: Dietary ornithine affects the tissue protein synthesis rate in young rats.
abstract: The purpose of this study was to determine whether ornithine affects the rate of tissue protein synthesis in male rats. Two experiments were done on five or two groups of young rats (5 wk) given diets containing 0.15, 0.3, 0.5 or 0.7% ornithine-HCl added to a 20% casein diet for 1 d (only one 3 h period) (Experiment 1), and given a diet containing 0 or 0.7% ornithine-HCl added to a 20% casein diet for 10 d (Experiment 2). The plasma concentration of growth hormone (GH) was the highest in rats fed 0.5 and 0.7% ornithine added to the 20% casein diet. The fractional rates of protein synthesis in brain regions, liver and gastrocnemius muscle increased significantly with the 20% casein+0.7% ornithine diet compared with the 20% casein diet. In brain regions, liver and gastrocnemius muscle, the RNA activity [g protein synthesized/(g RNA·d)] significantly correlated with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was not related to the fractional rate of protein synthesis in any organ. The present results suggest that the treatment of young rats with ornithine is likely to increase the concentration of plasma GH and the rate of protein synthesis in the tissues, and that RNA activity is at least partly related to the fractional rate of tissue protein synthesis.
authors.affiliation: Faculty of Early Childhood Care and Education, Ohkagakuen University, Toyoake, Aichi, Japan.
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Tujioka
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamada
authors.forename: Mami
authors.initials: M
authors.lastname: Aoki
authors.forename: Koji
authors.initials: K
authors.lastname: Morishita
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Hayase
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Yokogoshi
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002364:Caseins / Q000008:administration & dosage; D004032:Diet; D004305:Dose-Response Relationship, Drug; D013006:Growth Hormone / Q000097:blood; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D009952:Ornithine / Q000008:administration & dosage*; D014176:Protein Biosynthesis / Q000187:drug effects*; D012313:RNA / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002364:Caseins; D012313:RNA; D013006:Growth Hormone; D009952:Ornithine