Search results for "Skeletal muscle"
showing 10 items of 430 documents
Type IV collagen and laminin in slow and fast skeletal muscle in rats--effects of age and life-time endurance training.
1988
The changes in the biochemical composition of basement membrane (BM) in slow-twitch (m. soleus, MS) and fast-twitch (m. rectus femoris, MRF) skeletal muscles of rats were studied during aging and life-time endurance training (treadmill running). The concentrations of the 7S domain of type IV collagen and of the P2 fragment of laminin were determined with radioimmunoassays in the muscles of rats aged 1, 2, 4, 10, and 24 months. The concentration of type IV collagen was higher in MS than in MRF and increased significantly with age. At older ages, the concentration tended to be higher in the MS of trained than untrained rats. The concentration of laminin was significantly higher in MRF than in…
OGT and OGA expression in postmenopausal skeletal muscle associates with hormone replacement therapy and muscle cross-sectional area
2013
Protein glycosylation via O-linked N-acetylglucosaminylation (O-GlcNAcylation) is an important post-translational regulatory mechanism mediated by O-GlcNAc transferase (OGT) and responsive to nutrients and stress. OGT attaches an O-GlcNAc moiety to proteins, while O-GlcNAcase (OGA) catalyzes O-GlcNAc removal. In skeletal muscle of experimental animals, prolonged increase in O-GlcNAcylation associates with age and muscle atrophy. Here we examined the effects of hormone replacement therapy (HRT) and power training (PT) on muscle OGT and OGA gene expression in postmenopausal women generally prone to age-related muscle weakness. In addition, the associations of OGT and OGA gene expressions with…
Glucose 6-P dehydrogenase delays the onset of frailty by protecting against muscle damage.
2021
Background: Frailty is a major age-associated syndrome leading to disability. Oxidative damage plays a significant role in the promotion of frailty. The cellular antioxidant system relies on reduced nicotinamide adenine dinucleotide phosphate (NADPH) that is highly dependent on glucose 6-P dehydrogenase (G6PD). The G6PD-overexpressing mouse (G6PD-Tg) is protected against metabolic stresses. Our aim was to examine whether this protection delays frailty. Methods: Old wild-type (WT) and G6PD-Tg mice were evaluated longitudinally in terms of frailty. Indirect calorimetry, transcriptomic profile, and different skeletal muscle quality markers and muscle regenerative capacity were also investigate…
The effects of rapid weight loss on skeletal muscle in judo athletes
2020
Abstract Objective To observe the effect of rapid weight loss (RWL) methods over 3 days on muscle damage in judokas. Methods Eighteen judokas participated in this crossover study, meaning that judo athletes were subjected to exercise-only phase (4 days) and RWL phase (3 days). Subjects were tested for myoglobin, creatine kinase, aldolase, hemoglobin, and hematocrit values on seven consecutive days. These biomarkers served as indicators of acute muscle damage. Results During the exercise-only phase, no significant changes were observed. Myoglobin (Mb) (p < 0.001), creatine kinase (CK) (p < 0.001) and aldolase (ALD) (p < 0.001) significantly increased only during the RWL phase, as we…
Effects of time of day on resistance exercise-induced anabolic signaling in skeletal muscle
2013
This study examined the effect of morning versus afternoon exercise on acute responses in phosphorylation of proteins regulating muscle size and metabolism. Twenty-two untrained men, divided into the morning (n = 11) or afternoon (n = 11) group, performed maximal isometric leg extensions before and after resistance loading at 07:30–08:30 h and 16:00–17:00 h, respectively. Muscle pre- and postloading biopsies were analyzed for phosphorylated Akt, p70S6K, rpS6, p38 mitogen-activated protein kinase (MAPK), Erk1/2, and eukaryotic elongation factor (eEF) 2. Muscle force declined after exercise in both groups (p < 0.001). p70S6K Thr389 (p < 0.05) and Thr421/Ser424 and rpS6 (all p < 0.001) increas…
Antioxidant supplements in exercise: worse than useless?
2012
TO THE EDITOR: In a recent paper by Higashida et al. (5), the authors report that very large doses of antioxidant vitamins do not prevent the exercise-induced adaptive responses of muscle mitochondria, GLUT4, and insulin action to exercise. As clearly stated in the paper, their data disagree with those reported by three independent research groups from Germany (14), Australia (17), and Spain (4). Using a significantly different experimental protocol regarding exercise training intensity and duration, antioxidant supplementation (doses and types of antioxidants), and molecular parameters analyzed (mRNA vs. protein levels), Higashida et al. compared their data with ours and came to exactly th…
A novel nutrient blend mimics calorie restriction transcriptomics differentially in multiple tissues of mice
2017
Identification of caloric restriction mimetics (CRMs), compounds that mimic the beneficial effects of caloric restriction (CR) without restriction of dietary energy would be an advancement in anti-aging science. The present study investigated whether the transcriptional profiles of a putative CRM nutrient blend could mimic that of CR in diverse tissues following long-term feeding in B6C3F1 male mice. Study design: Young Controls (YC; 5 mo.) and 3 groups treated from 14-30 mo.: Old Controls (OC), Old CR (OCR; 25% CR) and Old Supplemented (OS); n=7/group. Gene expression profiling in cerebral cortex (CCT), skeletal muscle (gastrocnemius)(SKL), heart (HRT), white adipose tissue (WAT) and liver…
Physical activity responsive miRNAs – Potential mediators of training responses in human skeletal muscle?
2013
1. The basics of miRNA-mediated regulation The plasticity of skeletal muscle is of utmost importance for responding to and coping with environmental demands that emerge from changes in physical activity patterns, nourishment, hormonal status, and health. As is well known, a sedentary lifestyle, aging, immobilization, and chronic diseases are associated with reduced muscle mass and function, while regular exercise improves muscle function and reduces the rate of decrement throughout life. 1 However, we do not have a complete understanding of the molecular factors controlling skeletal muscle adaptation to exercise stimuli. Recently identified microRNA molecules (miRNAs) have rapidly gained at…
PO-201 Aging attenuates the effect of aerobic capacity in muscle and serum metabolic profile but not in white adipose tissue
2018
Objective Aerobic capacity is a quantitative predictor of the morbidity and mortality in many diverse patient populations. While aging is the main factor affecting aerobic capacity. The present study aimed to assess the effect of aerobic capacity and aging on metabolic profile in rats and to investigate the metabolic interactions between white adipose tissue (WAT), muscle and serum.
 Methods In this study, we used rat models that were selectively bred to differ in maximal running capacity (High capacity runners (HCR) and Low capacity runners (LCR)). Part of the rats were sacrificed after 9 months and the rest at 21 months. The effect of aerobic capacity on metabolic profile was assesse…
Expression of different isoforms of nitric oxide synthase in experimentally denervated and reinnervated skeletal muscle.
1997
Denervated muscle fibers express enhanced levels of stress and apoptosis-associated proteins and undergo apoptosis. In experimentally denervated and reinnervated rat facial muscle, we now evaluate changes in the expression patterns of different isoforms of nitric oxide synthase (NOS)-generating nitric oxide (NO), which mediates oxidative stress and apoptosis. Physiological expression of NOS corresponds to a constant sarcolemmal staining pattern for neuronal NOS (nNOS) and a patchy sarcolemmal and weak sarcoplasmic labeling for the endothelial NOS-isoform, with no expression for inducible NOS (iNOS). Denervated muscle displayed distinct downregulation of nNOS with preserved expression of dys…