Document Detail


Ingestion of casein and whey proteins result in muscle anabolism after resistance exercise.
MedLine Citation:
PMID:  15570142     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: Determination of the anabolic response to exercise and nutrition is important for individuals who may benefit from increased muscle mass. Intake of free amino acids after resistance exercise stimulates net muscle protein synthesis. The response of muscle protein balance to intact protein ingestion after exercise has not been studied. This study was designed to examine the acute response of muscle protein balance to ingestion of two different intact proteins after resistance exercise. METHODS: Healthy volunteers were randomly assigned to one of three groups. Each group consumed one of three drinks: placebo (PL; N = 7), 20 g of casein (CS; N = 7), or whey proteins (WH; N = 9). Volunteers consumed the drink 1 h after the conclusion of a leg extension exercise bout. Leucine and phenylalanine concentrations were measured in femoral arteriovenous samples to determine balance across the leg. RESULTS: Arterial amino acid concentrations were elevated by protein ingestion, but the pattern of appearance was different for CS and WH. Net amino acid balance switched from negative to positive after ingestion of both proteins. Peak leucine net balance over time was greater for WH (347 +/- 50 nmol.min(-1).100 mL(-1) leg) than CS (133 +/- 45 nmol.min(-1).100 mL(-1) leg), but peak phenylalanine balance was similar for CS and WH. Ingestion of both CS and WH stimulated a significantly larger net phenylalanine uptake after resistance exercise, compared with the PL (PL -5 +/- 15 mg, CS 84 +/- 10 mg, WH 62 +/- 18 mg). Amino acid uptake relative to amount ingested was similar for both CS and WH (approximately 10-15%). CONCLUSIONS: Acute ingestion of both WH and CS after exercise resulted in similar increases in muscle protein net balance, resulting in net muscle protein synthesis despite different patterns of blood amino acid responses.
Authors:
Kevin D Tipton; Tabatha A Elliott; Melanie G Cree; Steven E Wolf; Arthur P Sanford; Robert R Wolfe
Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  36     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2004 Dec 
Date Detail:
Created Date:  2004-11-30     Completed Date:  2005-02-25     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2073-81     Citation Subset:  IM; S    
Affiliation:
Metabolism Unit, Shriners Hospitals for Children and Department of Surgery, The University of Texas Medical Branch, Galveston, TX 77550, USA. ktipton@utmb.edu
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MeSH Terms
Descriptor/Qualifier:
Administration, Oral
Adult
Caseins / administration & dosage,  pharmacology*
Exercise / physiology*
Female
Humans
Leg / physiology
Leucine / analysis
Male
Milk Proteins / administration & dosage,  pharmacology*
Muscle, Skeletal / physiology*
Phenylalanine / analysis
Placebos
Weight Lifting / physiology
Grant Support
ID/Acronym/Agency:
M01 RR 00073/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Caseins; 0/Milk Proteins; 0/Placebos; 0/whey protein; 61-90-5/Leucine; 63-91-2/Phenylalanine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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