Increased p70s6k phosphorylation during intake of a protein-carbohydrate drink following resistance exercise in the fasted state

Eur J Appl Physiol. 2010 Mar;108(4):791-800. doi: 10.1007/s00421-009-1289-x.

Abstract

The present study aimed at comparing the responses of myogenic regulatory factors and signaling pathways involved in muscle protein synthesis after a resistance training session performed in either the fasted or fed state. According to a randomized crossover study design, six young male subjects participated in two experimental sessions separated by 3 weeks. In each session, they performed a standardized resistance training. After the sessions, they received during a 4-h recovery period 6 ml/kg b.w. h of a solution containing carbohydrates (50 g/l), protein hydrolysate (33 g/l), and leucine (16.6 g/l). On one occasion, the resistance exercise session was performed after the intake of a carbohydrate-rich breakfast (B), whereas in the other session they remained fasted (F). Needle biopsies from m. vastus lateralis were obtained before (Rest), and 1 h (+1h) and 4 h (+4h) after exercise. Myogenin, MRF4, and MyoD1 mRNA contents were determined by RT-PCR. Phosphorylation of PKB (protein kinase B), GSK3, p70(s6k) (p70 ribosomal S6 kinase), eIF2B, eEF2 (eukaryotic elongation factor 2), ERK1/2, and p38 was measured via western blotting. Compared with F, the pre-exercise phosphorylation states of PKB and p70(s6k) were higher in B, whereas those of eIF2B and eEF2 were lower. During recovery, the phosphorylation state of p70(s6k) was lower in B than in F (p = 0.02). There were no differences in basal mRNA contents between B and F. However, compared with F at +1h, MyoD1 and MRF4 mRNA contents were lower in B (p < 0.05). Our results indicate that prior fasting may stimulate the intramyocellular anabolic response to ingestion of a carbohydrate/protein/leucine mixture following a heavy resistance training session.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Blood Chemical Analysis
  • Cross-Over Studies
  • Dietary Carbohydrates / administration & dosage*
  • Dietary Carbohydrates / pharmacology
  • Dietary Proteins / administration & dosage*
  • Dietary Proteins / pharmacology
  • Drinking / physiology
  • Exercise Test
  • Fasting / physiology*
  • Feeding Methods
  • Humans
  • Male
  • Phosphorylation / drug effects
  • Protein Kinases / metabolism*
  • Resistance Training*
  • Ribosomal Protein S6 Kinases, 70-kDa / metabolism*
  • Up-Regulation
  • Young Adult

Substances

  • Dietary Carbohydrates
  • Dietary Proteins
  • Protein Kinases
  • Ribosomal Protein S6 Kinases, 70-kDa