TY - JOUR

T1 - Positive muscle protein net balance and differential regulation of atrogene expression after resistance exercise and milk protein supplementation

AU - Reitelseder, Søren

AU - Agergaard, Jakob

AU - Doessing, Simon

AU - Helmark, Ida C

AU - Schjerling, Peter

AU - van Hall, Gerrit

AU - Kjaer, Michael

AU - Holm, Lars

PY - 2014/2

Y1 - 2014/2

N2 - 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.

AB - 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.

KW - Adult

KW - Blood Flow Velocity

KW - Body Mass Index

KW - Body Weight

KW - Caseins

KW - Dietary Supplements

KW - Exercise

KW - Forkhead Transcription Factors

KW - Humans

KW - Insulin-Like Growth Factor I

KW - Leg

KW - Leucine

KW - Male

KW - Milk Proteins

KW - Muscle Proteins

KW - Muscle, Skeletal

KW - Physical Endurance

KW - RNA, Messenger

KW - SKP Cullin F-Box Protein Ligases

KW - Ubiquitin-Protein Ligases

KW - Up-Regulation

KW - Young Adult

U2 - 10.1007/s00394-013-0530-x

DO - 10.1007/s00394-013-0530-x

M3 - Journal article

VL - 53

SP - 321

EP - 333

JO - European Journal of Nutrition

JF - European Journal of Nutrition

SN - 1436-6207

IS - 1

ER -