The effect of a bout of resistance exercise on skeletal muscle protein metabolism after severe fasting.
Kohei SaseKohei KidoSatoru AtoSatoshi FujitaPublished in: Physiological reports (2020)
Resistance exercise (RE) activates the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway and increases muscle protein synthesis. Severe fasting induces 5' adenosine monophosphate-activated protein kinase (AMPK), which attenuates mTORC1 activation. However, the effect of RE on the response of mTORC1 signaling proteins after a period of severe fasting is unclear. We investigated the effect of RE on rat skeletal muscle protein metabolism after a period of severe fasting. We hypothesized that RE-induced activation of mTORC1 signaling protein attenuates protein breakdown by autophagy. Male Sprague-Dawley rats were divided into ordinary-fed (C) and 72-h fasting (F) groups. A bout of RE was replicated by percutaneous electrical stimulation in the right gastrocnemius muscle. The tuberous sclerosis complex 2 (TSC2) Ser1387 and autophagy marker of microtubule-associated protein 1A/1B-light chain 3-II (LC3B-II) expression of the F group increased twice that of the C group in sedentary state (P < 0.05). RE activated the mTORC1 signaling pathway in both groups (P < 0.05); however, in the F group, the magnitude of p70S6K (Thr389) phosphorylation was lower by 40% of that of the C group (P < 0.05). Protein synthesis after RE was increased by 50% from the level at sedentary state in the C group (P < 0.05), but not in the F. In the F group, the expression of LC3B-II at 3 h after RE was decreased by almost 25% from the level at sedentary state (P < 0.05). Our results suggest that RE suppressed fasting-induced autophagy but did not increase protein synthesis during severe fasting in rat skeletal muscle.
Keyphrases
- skeletal muscle
- insulin resistance
- signaling pathway
- blood glucose
- physical activity
- protein kinase
- early onset
- oxidative stress
- binding protein
- cell death
- drug induced
- endoplasmic reticulum stress
- adipose tissue
- amino acid
- poor prognosis
- pi k akt
- protein protein
- epithelial mesenchymal transition
- metabolic syndrome
- high intensity
- induced apoptosis
- type diabetes
- blood pressure
- mass spectrometry
- glycemic control
- cell proliferation
- ultrasound guided
- high speed
- radiofrequency ablation
- liquid chromatography
- high resolution mass spectrometry