Positive muscle protein net balance and differential regulation of atrogene expression after resistance exercise and milk protein supplementation

Eur J Nutr. 2014 Feb;53(1):321-33. doi: 10.1007/s00394-013-0530-x. Epub 2013 May 3.

Abstract

Purpose: Resistance exercise and amino acid availability are positive regulators of muscle protein net balance (NB). However, anabolic responses to resistance exercise and protein supplementation deserve further elucidation. The purpose was to compare intakes of whey, caseinate (both: 0.30 g/kg lean body mass), or a non-caloric control after heavy resistance exercise on protein turnover and mRNA expressions of forkhead homeobox type O (FOXO) isoforms, muscle RING finger 1 (MuRF1), and Atrogin1 in young healthy males.

Methods: Protein turnover was determined by stable isotope-labeled leucine and femoral arteriovenous blood samples at rest and during 6-h recovery. Muscle biopsies were collected at -60 min (rest) and at 60, 210, and 360 min in the recovery period.

Results: During recovery, leucine NB was significantly higher in the protein groups compared to control (P < 0.001). Differences in leucine NB, rate of disappearance, and oxidation were observed in the early recovery period between whey and caseinate. FOXO1A and MuRF1 were upregulated at 60 and 210 min, and, in contrast, FOXO3 and Atrogin1 were downregulated at 210 and 360 min. For leucine rate of appearance and all FOXO and atrogene mRNA expressions, no differences were observed between groups.

Conclusions: Whey and caseinate were equally superior to control in the 6-h recovery period and displayed temporal differences with whey having a fast and superior effect in the early part of the recovery period. Effects on mRNA expressions indicate different regulatory mechanisms on the ubiquitin ligases MuRF1 and Atrogin1 in recovery from heavy resistance exercise.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Flow Velocity
  • Body Mass Index
  • Body Weight
  • Caseins / administration & dosage*
  • Dietary Supplements*
  • Exercise / physiology*
  • Forkhead Box Protein O1
  • Forkhead Transcription Factors / metabolism
  • Humans
  • Insulin-Like Growth Factor I / metabolism
  • Leg / physiology
  • Leucine / metabolism
  • Male
  • Milk Proteins / administration & dosage*
  • Muscle Proteins / metabolism*
  • Muscle, Skeletal / metabolism
  • Physical Endurance / drug effects*
  • Physical Endurance / physiology
  • RNA, Messenger / metabolism
  • SKP Cullin F-Box Protein Ligases / metabolism
  • Tripartite Motif Proteins
  • Ubiquitin-Protein Ligases / metabolism
  • Up-Regulation
  • Whey Proteins
  • Young Adult

Substances

  • Caseins
  • FOXO1 protein, human
  • Forkhead Box Protein O1
  • Forkhead Transcription Factors
  • IGF1 protein, human
  • Milk Proteins
  • Muscle Proteins
  • RNA, Messenger
  • Tripartite Motif Proteins
  • Whey Proteins
  • Insulin-Like Growth Factor I
  • FBXO32 protein, human
  • SKP Cullin F-Box Protein Ligases
  • TRIM63 protein, human
  • Ubiquitin-Protein Ligases
  • Leucine