title: Protein ingestion further augments S6K1 phosphorylation in skeletal muscle following resistance type exercise in males.
abstract: Our objective was to determine the impact of carbohydrate and/or protein ingestion before and after exercise on ribosomal protein S6 kinase (S6K1) and S6 phosphorylation status in human skeletal muscle tissue. Seven healthy, untrained men (22.5 +/- 0.9 y) were randomly assigned to 2 cross-over experiments. Before, immediately after, and 1 h after a single bout of resistance exercise, subjects consumed 0.3 g x kg(-1) carbohydrate with or without 0.3 g x kg(-1) protein hydrolysate (CHO+PRO and CHO, respectively). Muscle biopsies were taken before and immediately after exercise and after 1 and 4 h of postexercise recovery to determine 4E-BP1, S6K1 (both T(421)/S(424) and T(389)), and S6 phosphorylation status. Following resistance exercise, 4E-BP1 phosphorylation was reduced to a greater extent in the CHO treatment (-48 +/- 7%) than in the CHO+PRO treatment (-15 +/- 14%, P < 0.01). During recovery, 4E-BP1 phosphorylation increased in both experiments (P < 0.01), and tended to be higher in the CHO+PRO test (P = 0.08). S6K1 phosphorylation at T(421)/S(424) substantially increased following exercise and remained elevated during recovery with no differences between treatments. In contrast to the CHO treatment (-4 +/- 2%), S6K1 phosphorylation at T(389) was higher following exercise in the CHO+PRO treatment only (+78 +/- 2%, P < 0.01). During recovery, S6K1 phosphorylation at T(389) remained higher in CHO+PRO than in CHO (P < 0.05). S6 phosphorylation was substantially higher following exercise in the CHO+PRO (1.69 +/- 0.35) than in the CHO experiment (0.45 +/- 0.07, P < 0.01) and remained elevated during recovery (P < 0.05). We conclude that the availability of dietary protein further enhances phosphorylation of S6K1 during recovery from resistance type exercise.
authors.affiliation: Department of Movement Sciences, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht 6200 MD, The Netherlands. r.koopman@hb.unimaas.nl
authors.forename: René
authors.initials: R
authors.lastname: Koopman
authors.forename: Bart
authors.initials: B
authors.lastname: Pennings
authors.forename: Antoine H G
authors.initials: AH
authors.lastname: Zorenc
authors.forename: Luc J C
authors.initials: LJ
authors.lastname: van Loon
mesh_terms: D001786:Blood Glucose; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000378:metabolism; D004044:Dietary Proteins / Q000494:pharmacology*; D015444:Exercise / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000097:blood; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000235:genetics / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D007328:Insulin; D019344:Lactic Acid; C069329:RPS6KA1 protein, human; D038744:Ribosomal Protein S6 Kinases, 90-kDa