title: Effect of an amino acid, protein, and carbohydrate mixture on net muscle protein balance after resistance exercise.
abstract: This study tests the hypotheses that (a) a mixture of whey protein, amino acids (AA), and carbohydrates (CHO) stimulates net muscle protein synthesis to a greater extent than isoenergetic CHO alone after resistance exercise; and (b) that the stimulatory effect of a protein, AA, and CHO mixture will last beyond the 1st hour after intake. Eight subjects participated in 2 trials. In one (PAAC), they ingested 77.4 g CHO, 17.5 g whey protein, and 4.9 g AA 1 hr after resistance exercise. In the other (CON), 100 g CHO was ingested instead. They received a primed constant infusion of L-[2H5]-phenylalanine, and samples from femoral artery and vein, and biopsies from vastus lateralis were obtained. The area under the curve for net uptake of phenylalanine into muscle above pre-drink value was 128+/- 42 mg x leg(- 1) (PAAC) versus 32+/- 10 mg x leg (-1) (CON) for the 3 hr after the drink (p =.04). The net protein balance response to the mixture consisted of two components, one rapid immediate response, and a smaller delayed response about 90 min after drink, whereas in CON only a small delayed response was seen. We conclude that after resistance exercise, a mixture of whey protein, AA, and CHO stimulated muscle protein synthesis to a greater extent than isoenergetic CHO alone. Further, compared to previously reported findings, the addition of protein to an AA+ CHO mixture seems to extend the anabolic effect.
authors.affiliation: Metabolism Unit in the Department of Surgery at the Shriners Hospitals for Children/Galveston, University of Texas Medical Branch, 77550, USA.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Borsheim
authors.forename: Asle
authors.initials: A
authors.lastname: Aarsland
authors.forename: Robert R
authors.initials: RR
authors.lastname: Wolfe
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage / Q000378:metabolism*; D019540:Area Under Curve; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008894:Milk Proteins / Q000008:administration & dosage / Q000378:metabolism*; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D010649:Phenylalanine / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics; D014891:Weight Lifting / Q000502:physiology*; D000067816:Whey Proteins
chemical_list: D000596:Amino Acids; D004040:Dietary Carbohydrates; D008894:Milk Proteins; D009124:Muscle Proteins; D000067816:Whey Proteins; D010649:Phenylalanine