title: Periexercise coingestion of branched-chain amino acids and carbohydrate in men does not preferentially augment resistance exercise-induced increases in phosphatidylinositol 3 kinase/protein kinase B-mammalian target of rapamycin pathway markers indicative of muscle protein synthesis.
abstract: The effects of a single bout of resistance exercise (RE) in conjunction with periexercise branched-chain amino acid (BCAA) and carbohydrate (CHO) ingestion on skeletal muscle signaling markers indicative of muscle protein synthesis were determined. It was hypothesized that CHO + BCAA would elicit a more profound effect on these signaling markers compared with CHO. Twenty-seven males were randomly assigned to CHO, CHO + BCAA, or placebo (PLC) groups. Four sets of leg presses and leg extensions were performed at 80% 1 repetition maximum. Supplements were ingested 30 minutes and immediately before and after RE. Venous blood and muscle biopsy samples were obtained immediately before supplement ingestion and 0.5, 2, and 6 hours after RE. Serum insulin and glucose and phosphorylated levels of muscle insulin receptor substrate 1 (IRS-1), protein kinase B, mammalian target of rapamycin, phosphorylated 70S6 kinase, and 4E binding protein 1 were assessed. Data were analyzed by 2-way repeated-measures analysis of variance. Significant group × time interactions were observed for glucose and insulin (P < .05) showing that CHO and CHO + BCAA were significantly greater than PLC. Significant time main effects were observed for IRS-1 (P = .001), protein kinase B (P = .031), mammalian target of rapamycin (P = .003), and phosphorylated 70S6 kinase (P = .001). Carbohydrate and CHO + BCAA supplementation significantly increased IRS-1 compared with PLC (P = .002). However, periexercise coingestion of CHO and BCAA did not augment RE-induced increases in skeletal muscle signaling markers indicative of muscle protein synthesis when compared with CHO.
authors.affiliation: Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202, USA.
authors.forename: Maria Pontes
authors.initials: MP
authors.lastname: Ferreira
authors.affiliation: Department of Health Sciences, Northeastern University, Boston, MA 02115, USA.
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.affiliation: College of Health and Biomedicine, Victoria University, Melbourne, VIC, 8001, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Cooke
authors.affiliation: Department of Health and Kinesiology, Texas A&M University, College Station, TX 78743, USA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Kreider
authors.affiliation: Department of Health, Human Performance, and Recreation, Baylor University, Waco, TX 76798, USA. Electronic address: darryn_willoughby@baylor.edu.
authors.forename: Darryn S
authors.initials: DS
authors.lastname: Willoughby
mesh_terms: D000328:Adult; D000597:Amino Acids, Branched-Chain / Q000008:administration & dosage*; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage; D019587:Dietary Supplements; D004311:Double-Blind Method; D006801:Humans; D007328:Insulin / Q000097:blood; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000187:drug effects; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D055070:Resistance Training; D015398:Signal Transduction / Q000187:drug effects*; D020123:Sirolimus / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D055815:Young Adult
chemical_list: D000597:Amino Acids, Branched-Chain; D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D009124:Muscle Proteins; C546842:MTOR protein, human; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus
keywords: Branched-chain amino acids; Carbohydrate; Insulin; Men; Muscle protein synthesis