Preservation of skeletal muscle mass is of great importance for maintaining both metabolic health and functional capacity. Muscle mass maintenance is regulated by the balance between muscle protein breakdown and synthesis rates. Both muscle protein breakdown and synthesis rates have been shown to be highly responsive to physical activity and food intake. Food intake, and protein ingestion in particular, directly stimulates muscle protein synthesis rates. The postprandial muscle protein synthetic response to feeding is regulated on a number of levels, including dietary protein digestion and amino acid absorption, splanchnic amino acid retention, postprandial insulin release, skeletal muscle tissue perfusion, amino acid uptake by muscle, and intramyocellular signaling. The postprandial muscle protein synthetic response to feeding is blunted in many conditions characterized by skeletal muscle loss, such as aging and muscle disuse. Therefore, it is important to define food characteristics that modulate
Purpose: Erythropoietin (EPO) is a renal cytokine that is primarily involved in hematopoiesis while also playing a role in non-hematopoietic tissues expressing the EPO-receptor (EPOR). The EPOR is present in human skeletal muscle. In mouse skeletal muscle, EPO stimulation can activate the AKT serine/threonine kinase 1 (AKT) signaling pathway, the main positive regulator of muscle protein synthesis. We hypothesized that a single intravenous EPO injection combined with acute resistance exercise would have a synergistic effect on skeletal muscle protein synthesis via activation of the AKT pathway.Methods: Ten young (24.2 ± 0.9 years) and 10 older (66.6 ± 1.1 years) healthy subjects received a primed, constant infusion of [ring-13C6] L-phenylalanine and a single injection of 10,000 IU epoetin-beta or placebo in a double-blind randomized, cross-over design. 2 h after the injection, the subjects completed an acute bout of leg extension resistance exercise to stimulate skeletal muscle protein synthesis
TY - JOUR. T1 - Rapamycin administration in humans blocks the contraction-induced increase in skeletal muscle protein synthesis. AU - Drummond, Micah J.. AU - Fry, Christopher. AU - Glynn, Erin L.. AU - Dreyer, Hans C.. AU - Dhanani, Shaheen. AU - Timmerman, Kyle L.. AU - Volpi, Elena. AU - Rasmussen, Blake. PY - 2009. Y1 - 2009. N2 - Muscle protein synthesis and mTORC1 signalling are concurrently stimulated following muscle contraction in humans. In an effort to determine whether mTORC1 signalling is essential for regulating muscle protein synthesis in humans, we treated subjects with a potent mTORC1 inhibitor (rapamycin) prior to performing a series of high-intensity muscle contractions. Here we show that rapamycin treatment blocks the early (1-2 h) acute contraction-induced increase (∼40%) in human muscle protein synthesis. In addition, several downstream components of the mTORC1 signalling pathway were also blunted or blocked by rapamycin. For instance, S6K1 phosphorylation (Thr421/Ser424) ...
Age-related muscle wasting (sarcopenia) is accompanied by a loss of strength which can compromise the functional abilities of the elderly. Muscle proteins are in a dynamic equilibrium between their respective rates of synthesis and breakdown. It has been suggested that age-related sarcopenia is due to: i) elevated basal-fasted rates of muscle protein breakdown, ii) a reduction in basal muscle protein synthesis (MPS), or iii) a combination of the two factors. However, basal rates of muscle protein synthesis and breakdown are unchanged with advancing healthy age. Instead, it appears that the muscles of the elderly are resistant to normally robust anabolic stimuli such as amino acids and resistance exercise. Ageing muscle is less sensitive to lower doses of amino acids than the young and may require higher quantities of protein to acutely stimulate equivalent muscle protein synthesis above rest and accrue muscle proteins. With regard to dietary protein recommendations, emerging evidence suggests ...
BACKGROUND. Systemic inflammation and muscle wasting are highly prevalent and coexist in patients on maintenance hemodialysis (MHD). We aimed to determine the effects of systemic inflammation on skeletal muscle protein metabolism in MHD patients. METHODS. Whole body and skeletal muscle protein turnover were assessed by stable isotope kinetic studies. We incorporated expressions of E1, E214K, E3αI, E3αII, MuRF-1, and atrogin-1 in skeletal muscle tissue from integrin β1 gene KO CKD mice models. RESULTS. Among 129 patients with mean (± SD) age 47 ± 12 years, 74% were African American, 73% were male, and 22% had diabetes mellitus. Median high-sensitivity C-reactive protein (hs-CRP) concentration was 13 (interquartile range 0.8, 33) mg/l. There were statistically significant associations between hs-CRP and forearm skeletal muscle protein synthesis, degradation, and net forearm skeletal muscle protein balance (P , 0.001 for all). The associations remained statistically significant after ...
BACKGROUND: The progressive loss of skeletal muscle mass with aging is attributed to a disruption in the regulation of skeletal muscle protein turnover. OBJECTIVE: We investigated the effects on whole-body protein balance and mixed-muscle protein synthesis rates of the ingestion of carbohydrate with or without protein and free leucine after simulated activities of daily living. DESIGN: Eight elderly (75 +/- 1 y) and 8 young (20 +/- 1 y) lean men were randomly assigned to 2 crossover experiments in which they consumed either carbohydrate (CHO) or carbohydrate plus protein and free leucine (CHO+Pro+Leu) after performing 30 min of standardized activities of daily living. Primed, continuous infusions with L-[ring-13C6]phenylalanine and L-[ring-2H2]tyrosine were applied, and blood and muscle samples were collected to assess whole-body protein turnover and the protein fractional synthetic rate in the vastus lateralis muscle over a 6-h period. RESULTS: Whole-body phenylalanine and tyrosine flux were ...
An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein. Am. J. Physiol. 273 (Endocrinol. Metab. 36): El22-E129, 1997. -Six normal untrained men were studied during the intravenous infusion of a balanced amino acid mixture (-0.15 g. kg-l. h-l for 3 h) at rest and after a leg resistance exercise routine to test the influence of exercise on the regulation of muscle protein kinetics by hyperaminoacidemia. Leg muscle protein kinetics and transport of selected amino acids (alanine, phenylalanine, leucine, and lysine) were isotopically determined using a model based on arteriovenous blood samples and muscle biopsy. The intravenous amino acid infusion resulted in comparable increases in arterial amino acid concentrations at rest and after exercise, whereas leg blood flow was 64 +/- 5% greater after exercise than at rest. During hyperaminoacidemia, the increases in amino acid transport above basal were 30-100% greater after exercise than at rest. Increases in muscle ...
We have previously shown that non-specific blockade of the cyclooxygenase (COX) enzymes in skeletal muscle eliminates the normal increase in muscle protein synthesis following resistance exercise. The current study tested the hypothesis that this COX-mediated increase in postexercise muscle protein synthesis is specifically regulated by the COX-2 isoform. Sixteen males (23 ± 1 yr, 177 ± 2 cm, 81.5 ± 3.4 kg) were randomly assigned to one of two groups that received three doses of either a specific COX-2 inhibitor (celecoxib; 200 mg per dose, 600 mg total) or a placebo during the 24 hours following a single bout of resistance exercise with the knee extensors. Skeletal muscle fractional synthesis rate (FSR) was measured at rest and 24 hours postexercise using a primed constant infusion of [2H5]phenylalanine coupled with muscle biopsies of the vastus lateralis. Mixed muscle FSR was increased following exercise to a greater extent (206%, P,0.05) in the COX-2 group (0.052 ± 0.014 %Ih) as compared ...
There were 2 primary goals of this work. The first was to develop a minimally invasive method for measuring integrated rates of skeletal muscle protein synthesis over a period of days to weeks based on a single blood measurement - i.e., without the need for a physical sample of the tissue. Muscle biopsies are not likely to be widely used in the clinical setting, so a blood test of muscle protein synthesis rates that could be monitored over time would be attractive for drug development, as well as clinical management of disorders of muscle, including sarcopenia and cachexia. Because changes in muscle protein synthesis rates have been shown to occur rapidly in response to anabolic therapies and to predict subsequent changes in muscle mass, strength, and performance (5, 8-10), the availability of a blood test for skeletal muscle protein synthesis rates would greatly simplify translational drug development and monitoring of treatment efficacy in this growing, unmet medical need.. We describe here an ...
It is thought that the production of muscle protein after a meal in response to consuming protein and/or amino acids is impaired in the elderly compared to the young. Also, consuming carbohydrates at the same time increases secretion of the hormone insulin and increases muscle protein production in the young. However, it is unclear how the elderly respond to the combined intake of protein and carbohydrates. Likewise, consuming the amino acid leucine may also increase muscle protein production. Adding carbohydrate or leucine to protein may represent effective strategies to overcome the impaired muscle protein production in the elderly. This study consists of three substudies. The aim of the first study is to determine if the response to combined protein and carbohydrate intake is different between young and elderly men. The aim of the second study is to investigate whether consuming carbohydrate as well increases muscle protein production in elderly men. The aim of the third study is to examine ...
Victor R. Preedy, James Keating, Timothy J. Peters; Ethanol-Induced Reductions in Skeletal Muscle Protein Synthesis in the Rat in Vivo. Clin Sci (Lond) 1 October 1990; 79 (s23): 7P. doi: https://doi.org/10.1042/cs079007P. Download citation file:. ...
The purpose of this investigation was to examine the effects of training either once or three times/day on the principal stages of skeletal muscle. The experiments were carried out on male albino rats fed either 3 or 5 times/day a diet containing 20% protein. Experimental animals swam either once or 3 times/day, 6 days/week for 10 weeks with weights attached. The total duration of daily activity was equal for both groups and at 10 weeks each animal was swimming for 60 min/day with 3% of his body weight attached. All the animals were examined at rest after the 10-week training programs. The adequacy of the weight-loading and training schedules was estimated by body weight dynamics and such energy metabolites as creatine phosphate and glycogen. Skeletal muscle RNA and protein synthesis were studied by means of 14C-orotic acid and 14C-leucine incorporation, respectively. Quadriceps and gastrocnemius muscles were used for analysis in all experiments. It was found that the increase in the number of daily
Optimal muscle protein synthesis requires a pulsatile increase in branch-chain amino acids (particularly leucine) with or without concomitant pulses in insulin levels. Pancreatic substrate clamp studies have demonstrated that insulin and branch-chain amino acids independently increase muscle synthesis with the effects of both being additive [45, 46]. Animal data demonstrates that muscle protein synthesis following a meal is rapid (within 30 min) and sustained for about 2 h but then declines toward baseline in parallel with the postprandial changes in circulating insulin and amino acids [34, 47]. Bohe and colleagues measured the latency and duration of the stimulation of human muscle protein synthesis during a continuous infusion of amino acids [48]. The rate of muscle protein synthesis increased after 30 min and reached a peak at 2 h rapidly returning to basal levels by 4 h despite continuous amino acid availability. In healthy individuals at rest, muscle protein synthesis displays a saturable ...
Insulin action on muscle protein kinetics and amino acid transport during recovery after resistance exercise. Biolo, Gianni; Williams, Bradley D.; Fleming, R.Y. Declan; Wolfe, Robert R. // Diabetes;May99, Vol. 48 Issue 5, p949 Determines the role of insulin on muscle protein kinetics and amino acid transport after heavy resistance exercise. Effect of insulin infusion on plasma insulin and glucose concentrations; Rate of muscle protein synthesis and degradation during hyperinsulinemia at rest and after exercise; Amino... ...
Abstracts of the Eighth European Conference on Muscle and Motility including the Erwin Riesch Symposium on Muscle Proteins - Polymorphism and Isoforms Heidelberg, 17-20 September ...
Sarcopenia is a well-known phenomenon in elderly individuals and resistance exercise together with sufficient amino acid (AA) availability has proved to be a counteractive implement. However, the source of AA and supplement timing require further investigation. The objective was to compare muscle protein synthesis (MPS) to intakes of whey and caseinate after heavy resistance exercise in healthy elderly individuals, and, furthermore, to compare the timing effect of caseinate intake. Twenty-four elderly men and women (mean ± SEM; 68 ± 1 years) were randomized to one of four groups: caseinate intake before exercise (CasPre), caseinate intake immediately after exercise (CasPost), whey intake immediately after exercise (Whey), or intake of a non-caloric control drink (Control). Muscle myofibrillar and collagen fractional synthesis rates (FSR) were measured by a primed continuous infusion of l-[1-13C]leucine using labeled proteins during a 6-h recovery period. No differences were observed in muscle ...
I think its fair to say that there are very few players who are not actively looking to increase their muscle mass or improve their body composition. Research suggests that additional muscle mass can improve the predicted success in some team sports such as rugby1. Building muscle is a multi-faceted approach and the following 3 tips will help you maximise those gains and improve performance.. Tip #1 - Engage in resistance training. Resistance Training (RT) is the single most important factor in building muscle. During RT muscle fibres are broken down and muscle protein synthesis (MPS) is increased. However, although MPS is increased, supporting nutrition in the form of protein is needed in order to ensure MPS is greater than muscle protein breakdown (MPB) and muscle grows. There is no change in muscle growth after one RT session but instead muscle hypertrophy is due to the accumulation of muscle protein in response to each individual bout of RT training plus protein that occurs ...
If patients could recognise themselves, or anyone else could recognise a patient from your description, please obtain the patients written consent to publication and send them to the editorial office before submitting your response [Patient consent forms] ...
Purpose: We have previously shown that the aminoacidemia caused by the consumption of a rapidly digested protein after resistance exercise enhances muscle protein synthesis (MPS) more than the amino acid (AA) profile associated with a slowly digested protein. Here, we investigated whether differential feeding patterns of a whey protein mixture commencing before exercise affect postexercise intracellular signaling and MPS. Methods: Twelve resistance-trained males performed leg resistance exercise 45 min after commencing each of three volume-matched nutrition protocols: placebo (PLAC, artificially sweetened water), BOLUS (25 g of whey protein + 5 g of leucine dissolved in artificially sweetened water; 1× 500 mL), or PULSE (15× 33-mL aliquots of BOLUS drink every 15 min). Results: The preexercise rise in plasma AA concentration with PULSE was attenuated compared with BOLUS (P less than 0.05); this effect was reversed after exercise, with two-fold greater leucine concentrations in PULSE compared ...
It turns out that only slight elevations of insulin above basal levels are all thats required to blunt muscle catabolic effects. Just consuming protein alone is enough to elicit a release of insulin that is sufficient to interact with the ingested amino acids in promoting muscle protein synthesis. Leucine alone is known to promote the release of insulin. This explains the recent studies showing that protein alone is enough to boost muscle protein synthesis following training. Indeed, one study showed that boosting insulin levels 30-times above fasting level did not further boost muscle protein synthesis if blood levels of amino acids were high. Just consuming protein alone, especially whey, which is rich in leucine, is enough to boost insulin levels 2-3-fold above resting levels. This level of insulin alone is enough to provide the anti-catabolic effects of insulin following exercise. Other studies show that adding 30 or 90 grams of carbs to 20 grams of protein does not boost muscle protein ...
Save 32% CytoSport - Muscle Milk Banana Creme 2.47 Pounds Muscle Milk Protein Powder Everyday Performance 310 Calories Per 2 Scoops 32g Protein Per 2 Scoops 20 Vitamins & Minerals Free of Banned Substances Gluten Free The Power of Protein Protein you eat breaks down into amino acids in the body, which support muscle growth, repair and maintenance Consuming both fast and slow release proteins, like those found in Muscle Milk Protein Powder, keeps your body in positive protein balance Protein after exercise aids in recovery and helps build lean muscle 32 Grams of Protein --Build lean muscles --Recover after exercise 20 Vitamins & Minerals --Antioxidant vitamins A, C and E --Vitamin D, Calcium, Magnesium and Phosphorus for strong bones BCAA (Branched Chain Amino Acids) --Leucine, Isoleucine, Valine help support muscle maintenance and growth --Leucine triggers muscle protein growth and helps prevent muscle protein breakdown. Protein Comparisons 2 Scoops of Muscle Milk = 4 Jumbo Eggs 2 Scoops of Muscle Milk
Save 32% CytoSport - Muscle Milk Cake Batter 2.47 Pounds Muscle Milk Protein Powder Everyday Performance 310 Calories Per 2 Scoops 32g Protein Per 2 Scoops 20 Vitamins & Minerals Free of Banned Substances Gluten Free The Power of Protein Protein you eat breaks down into amino acids in the body, which support muscle growth, repair and maintenance Consuming both fast and slow release proteins, like those found in Muscle Milk Protein Powder, keeps your body in positive protein balance Protein after exercise aids in recovery and helps build lean muscle 32 Grams of Protein --Build lean muscles --Recover after exercise 20 Vitamins & Minerals --Antioxidant vitamins A, C and E --Vitamin D, Calcium, Magnesium and Phosphorus for strong bones BCAA (Branched Chain Amino Acids --Leucine, Isoleucine, Valine help support muscle maintenance and growth --Leucine triggers muscle protein growth and helps prevent muscle protein breakdown. Protein Comparisons 2 Scoops of Muscle Milk = 4 Jumbo Eggs 2 Scoops of Muscle Milk =
Muscle protein synthesis is stimulated by resistance training and protein intake. Muscle growth is the outcome of effective MPS response in our body.
Autor: Schraders, M. et al.; Genre: Zeitschriftenartikel; Im Druck veröffentlicht: 2011; Keywords: Adolescent; Adult; Child; Child, Preschool; *Codon, Nonsense; DNA Mutational Analysis; Female; Frameshift Mutation; *Genes, X-Linked; Hearing Loss/*genetics/pathology; Humans; Insulin-Like Growth Factor I/genetics; Male; Middle Aged; Molecular Sequence Annotation; Muscle Proteins/*genetics; Pedigree; Polymorphism, Single Nucleotide; Sequence Analysis; Young Adult; Titel: Next-generation sequencing identifies mutations of SMPX, which encodes the small muscle protein, X-linked, as a cause of progressive hearing impairment
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Resistance coaching and subsequent intake of a protein-rich food encourages muscle mass hypertrophy and gains in muscle mass toughness by stimulating myofibrillar muscle protein synthesis (MPS) and inhibiting muscle protein breakdown (MPB).[108][109] The stimulation of muscle mass protein synthesis by resistance education happens by means of phosphorylation in the mechanistic target of rapamycin (mTOR) and subsequent activation of mTORC1, which ends up in protein biosynthesis while in the ribosome by means of phosphorylation of mTORC1s speedy targets (the p70S6 kinase and the translation repressor protein 4EBP1 ...
Resistance schooling and subsequent usage of the protein-loaded meal promotes muscle mass hypertrophy and gains in muscle mass power by stimulating myofibrillar muscle mass protein synthesis (MPS) and inhibiting muscle protein breakdown (MPB).[108][109] The stimulation of muscle protein synthesis by resistance schooling takes place through phosphorylation in the mechanistic concentrate on of rapamycin (mTOR) and subsequent activation of mTORC1, which results in protein biosynthesis within the ribosome by means of phosphorylation of mTORC1s quick targets (the p70S6 kinase and the translation repressor protein 4EBP1 ...
Bioactive peptides have been identified in a range of foods, including plant, milk and muscle, e.g., beef, chicken, pork and fish muscle proteins. Bioactive peptides from food proteins offer major potential for incorporation into functional foods and nutraceuticals. The aim of this paper is to present an outline of the bioactive peptides identified in the muscle protein of meat to date, with a focus on muscle protein from domestic animals and fish. The majority of research on bioactives from meat sources has focused on angiotensin-1-converting enzyme (ACE) inhibitory and antioxidant peptides.
Bioactive peptides have been identified in a range of foods, including plant, milk and muscle, e.g., beef, chicken, pork and fish muscle proteins. Bioactive peptides from food proteins offer major potential for incorporation into functional foods and nutraceuticals. The aim of this paper is to present an outline of the bioactive peptides identified in the muscle protein of meat to date, with a focus on muscle protein from domestic animals and fish. The majority of research on bioactives from meat sources has focused on angiotensin-1-converting enzyme (ACE) inhibitory and antioxidant peptides.
Sarcopenia seems to be attributed to a blunted muscle protein synthetic response to food intake and exercise. This blunted response could be the result of impaired protein digestion and absorption kinetics and lead to lower postprandial plasma amino acid availability.
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Its all about Amino Acids Skeletal muscle actively collaborates and participates in all amino acid exchanges with other tissues throughout the body, both at re
Muscle proteinsynthesis, as you already know, is required to construct muscle tissue. When ample leverageis created and sustained, these elements loosen their grip, permitting proteinsynthesis to consider off.* Subsequently, this promotes more substantial, far more immediate gains inmuscle mass, toughness, tone and definition.* BI will not be conscious of any othercompany that manufactures a protein powder with this type of substantial written content of MPI. MPIhas been often called the "leverage protein" for its capability to aid highanabolic leverage ...
Building muscle after 40 is definitely possible. In fact, you can still achieve the same level of muscle protein synthesis as someone in their 20s, however...
Since 1995, no-one has become in a position to duplicate MPs delectable flavor method or recognize its exact contents. Created by the labs R&D workforce around the course of not less than 5 time- and labor-intense rounds of audits, the flavor method is uncommon in many regards. By way of example, Whilst other protein nutritional supplements consist of added "filler" substances in order to handle flavor, texture and/or mixability difficulties, BI has preferred to conquer these challenges by introducing far more large-top quality proteins particularly combos ...
Produktbeschreibung: Milchmischgetränk aus Magermilch mit Zusatz von Milcheiweiß und Kohlenhydraten und einer Zuckerart Empfohlene Trainingsphasen: Muskelaufbauphase Kraftphase Definitionsphase (als Post-Workout Drink) Produkteigenschaften: liefert mehr Protein als Kohlenhydrate Proteine tragen zu einer Zunahme an Muskelmasse bei* ideal als Shake zwischendurch für alle aktiven Sportler Zufuhrempfehlung: 1 Flasche täglich Inhalt: 500 ml Dunkel lagern. Zutaten (Allergene…
Remember how we mentioned BCAA consists of three components of amino acids? Two of it, namely isoleucine and valine, are directly capable of producing energy and regulating blood sugar levels. Like we mentioned earlier, these amino acids do not metabolize in the liver but are instead broken down in your muscle itself, thus proving its significance in producing energy. This makes BCAA ideal for intense workouts because it will be used as an additional source of energy to keep your body fueled and going without tiring you out. These amino acids are also able to increase and preserve better your storage of glycogen, the component that keeps your body fueled and energized. All in all, BCAA helps fuel your body during intense workouts, prevents the breakdown of muscle protein while doing so, and preserves your bodys storage of glycogen. 2. Increases muscle growth. Consuming BCAA supplements will not only help speed up your muscle growth, but also protect and preserve your muscle mass. This links ...
Alcohol can hinder muscle growth by inhibiting muscle protein synthesis, and sports drinks - although beneficial in replacing lost micronutrients after hard training sessions that last an hour or longer - are often guilty of providing more calories, sodium, and sugar that the body needs. "Ive always enjoyed a big glass of water," he admits. "Every so often I have a sweet tea, but I know thats not great for me so I try not to drink a lot of it. I dont drink much alcohol. Nothing against it, but with my lifestyle, Im not around it. A big night for me is getting kids ready for bed and watching some TV ...
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The rest of the paper argues why this is the case on scaling grounds. They care about deriving this constant relationship, and estimating its magnitude (body-lengths-per-second), not exactly but to within a factor of ten.. They argue that that the moving speed is determined by three features shared universally among moving organisms. The first is that because all life forms are mostly water and more-or-less buoyant, they have roughly the density of water, 1 kg/L. The second is that all motility is caused by the contraction of muscle proteins that have a similar structure across all life-forms. Based on the non-covalent binding energy of these proteins and their diameter, the force-per-unit-area they can exert is roughly 20,000 N/m2. Could a square-meter cross section of muscle support two tons? Im picturing an elephant leg and I can believe it. The final feature is the metabolic rate per unit mass, which is related to an organisms ability to transfer heat across its surface. The paper states ...
1. Quadriceps muscle protein turnover was assessed in the post-absorptive state in six men immediately after the end of unilateral leg immobilization (37 ± 4 days) in a plaster cast after tibial fracture. A primed-constant intravenous infusion of l-[1-13C]leucine was administered over 7 h. Quadriceps needle biopsies, taken bilaterally at the end of the infusion, were analysed for muscle protein leucine enrichment with 13C.. 2. Quadriceps muscle protein synthetic rate, calculated from the fractional incorporation of [13C]leucine into protein compared with the average enrichment of blood α-ketoisocaproate, was 0.046 ±0.012%/h in the uninjured leg, but was only 0.034 ±0.007%/h in the quadriceps of the previously fractured leg (P , 0.05, means ± sd).. 3. Muscle RNA activity (i.e. protein synthetic rate per RNA) fell from 0.27 ±0.08 μg of protein synthesized h−1 μg−1 of RNA in the control leg to 0.14 ±0.03 μg of protein synthesized h−1 μg−1 of RNA in the immobilized leg (P , ...
Author: Mller, Rikke S. et al.; Genre: Journal Article; Published in Print: 2008-04-16; Title: Truncation of the Down syndrome candidate gene DYRK1A in two unrelated patients with microcephaly
Due to insufficient exercise training, skeletal mucle loss is beginning form 25 years old. Sarcopenia is the critical reason to effect activities of daily life in seniors. Strength training has been proven to be a great strategy to increase mucle mass and functions. Exercise training provokes skeletal muscle protein synthesis, in the meantime also causes muscle injury, induces muscle protien degradation and muscle cell inflammatory. Net muscle protein balace will become negative in nutrients or rest deficiency. Muscle biogenesis decreasing with aging may induce by signal transmit weakening in muscle protein synthesis pathway. Current studies showed that the phosphatidylinositol 3-kinase /AKT/mammalian target of rapamycin (PI3K/Akt/ mTOR) pathway is an important pathway to regulate skeletal muscle hypertrophy. Therefore, the first year, resveratrol is uesd as a nutriental ergogenic aid which may activate related protein expression of muscle synthesis pathway. In order to understand promotion or ...
Ingestion of sufficient dietary protein is a fundamental prerequisite for muscle protein synthesis and maintenance of muscle mass and function. Elderly people are often at increased risk for protein-energy malnutrition, sarcopenia, and a diminished quality of life. This study sought to compare chang …
Rationale: The giant protein titin plays key roles in myofilament assembly and determines the passive mechanical properties of the sarcomere. The cardiac titin molecule has 2 mayor elastic elements, the N2B and the PEVK region. Both have been suggested to determine the elastic properties of the heart with loss of function data only available for the N2B region.. Objective: The purpose of this study was to investigate the contribution of titins proline-glutamate-valine-lysine (PEVK) region to biomechanics and growth of the heart.. Methods and Results: We removed a portion of the PEVK segment (exons 219 to 225; 282 aa) that corresponds to the PEVK element of N2B titin, the main cardiac titin isoform. Adult homozygous PEVK knockout (KO) mice developed diastolic dysfunction, as determined by pressure-volume loops, echocardiography, isolated heart experiments, and muscle mechanics. Immunoelectron microscopy revealed increased strain of the N2B element, a spring region retained in the PEVK-KO. ...
1. We have used l-[1-13C,15N]leucine as the substrate tracer to study leucine and muscle protein metabolism across the forearm of eight normal fasting adults.. 2. The rates of protein synthesis and breakdown, de- and re-amination of leucine, and the oxidative de-carboxylation of its keto acid were calculated directly from the arteriovenous metabolite balances and isotope dilutions as described by the metabolic model.. 3. The results were compared with those obtained previously when subjects were fed. The effects of fasting on protein and leucine metabolism were a significant decrease in protein synthesis from 127 (sem 11; n = 6) to 70 (sem 6; n = 12) nmol of leucine min−-1 100 ml−-1 of forearm tissue (P , 0.001) and a marked decrease in leucine catabolism in the forearm muscle.. 4. This model has demonstrated that each subject was in negative protein balance across the forearm during fasting while positive during feeding, the mean values being −29(sem 5; n = 12) and + 39(sem 9; n = 6) nmol ...
The peroxisome proliferator-activated receptor γ (PPARγ) agonist rosiglitazone (Rosi) appears to provide protection against organ dysfunction during endotoxaemia. We examined the potential benefits of Rosi on skeletal muscle protein maintenance and carbohydrate metabolism during lipopolysaccharide (LPS)-induced endotoxaemia. Sprague-Dawley rats were fed either standard chow (control) or standard chow containing Rosi (8.5±0.1 mg.kg-1.day-1) for two weeks before and during 24 h continuous intravenous infusion of LPS (15 μg.kg-1.h-1) or saline. Rosi blunted LPS-induced increases in muscle tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) mRNA by 70% (P,0.05) and 64% (P,0.01), respectively. Furthermore, Rosi suppressed the LPS-induced reduction in phosphorylated AKT and phosphorylated Forkhead box O (FOXO) 1 protein, as well as the upregulation of muscle RING finger 1 (MuRF1; P,0.01) mRNA, and the LPS-induced increase in 20S proteasome activity (P,0.05). Accordingly, LPS reduced the ...
The active and passive contractile performance of skeletal muscle fibers largely depends on the myosin heavy chain (MHC) isoform and the stiffness of the titin spring, respectively. Open questions concern the relationship between titin-based stiffness and active contractile parameters, and titins importance for total passive muscle stiffness. Here, a large set of adult rabbit muscles (n = 37) was studied for titin size diversity, passive mechanical properties, and possible correlations with the fiber/MHC composition. Titin isoform analyses showed sizes between ∼3300 and 3700 kD; 31 muscles contained a single isoform, six muscles coexpressed two isoforms, including the psoas, where individual fibers expressed similar isoform ratios of 30:70 (3.4:3.3 MD). Gel electrophoresis and Western blotting of two other giant muscle proteins, nebulin and obscurin, demonstrated muscle type-dependent size differences of ≤70 kD. Single fiber and single myofibril mechanics performed on a subset of muscles ...