King Grub
2018-08-31, 10:54
The present study aimed at investigating fasting-induced responses in regulators and markers of autophagy in vastus lateralis muscle from untrained and trained human subjects. Untrained and trained subjects (based on level of maximum oxygen uptake, muscle CS activity and OXPHOS protein level) fasted for 36h with vastus lateralis muscle biopsies obtained at 2, 12, 24 and 36h after a standardized meal. Fasting reduced (p<0.05) skeletal muscle microtubule-associated protein-1A/1B light chain 3 (LC3)I, (LC3)II and adaptor protein sequestosome 1/p62 (p62) protein content in untrained subjects only. Moreover, skeletal muscle RAC-alpha serine/threonine-protein kinase (AKT)Thr308, AMP-activated protein kinase (AMPK)Thr172, Unc-51 like autophagy activating kinase 1 (ULK1)Ser555 phosphorylation state, as well as Bcl-2-interacting coiled-coil protein 1 (Beclin1) and ULK1Ser757 phosphorylation was lower (p<0.05) in trained than untrained subjects during fasting. In addition, the concentrations of several amino acids were lower (p<0.05) in trained than untrained, and the plasma concentration profile of several amino acids was different in untrained and trained subjects during fasting. Taken together, these findings suggest that 36h of fasting has effects on some mediators of autophagy in untrained human skeletal muscle and that training state influences the effect of fasting on autophagy signaling and on mediators of autophagy in skeletal muscle.
J Appl Physiol (1985). 2018 Aug 30. Training state and skeletal muscle autophagy in response to 36h of fasting.
J Appl Physiol (1985). 2018 Aug 30. Training state and skeletal muscle autophagy in response to 36h of fasting.