Search Results
Results 351 - 400 of 785
< 3 4 5 6 7 8 9 10 11 12 13 >
Gibala M J - - 1998
We examined the relationship between tricarboxylic acid (TCA) cycle intermediate (TCAI) pool size, TCA cycle flux (calculated from leg O2 uptake), and pyruvate dehydrogenase activity (PDHa) in human skeletal muscle. Six males performed moderate leg extensor exercise for 10 min, followed immediately by intense exercise until exhaustion (3.8 +/- 0.5 ...
Chesley A - - 1998
This study examined the effects of caffeine (Caf) ingestion on muscle glycogen use and the regulation of muscle glycogen phosphorylase (Phos) activity during intense aerobic exercise. In two separate trials, 12 untrained males ingested either placebo (Pl) or Caf (9 mg/kg body wt) 1 h before cycling at 80% maximum ...
Kiens B - - 1998
The utilization of muscle triacylglycerols was studied during and after prolonged bicycle ergometer exercise to exhaustion in eight healthy young men. Two days before exercise and in the postexercise recovery period, subjects were fed a carbohydrate-rich diet (65-70% of energy from carbohydrates). Exercise decreased muscle glycogen concentrations from 533 +/- ...
Howlett R A - - 1998
This study investigated the transformational and posttransformational control of skeletal muscle glycogen phosphorylase and pyruvate dehydrogenase (PDH) at three exercise power outputs [35, 65, and 90% of maximal oxygen uptake (VO2 max)]. Seven untrained subjects cycled at one power output for 10 min on three separate occasions, with muscle biopsies ...
Nakamura M - - 1998
Male Sprague-Dawley rats (n = 48, > 200 g) were progressively treadmill trained over 5 wk where they were running 60 min/d, 5 d/wk. One-half of the group consumed a high-fat diet (HF, 78.7% of energy), while one-half consumed a high-carbohydrate diet (HC, 68.7% of energy). On the day of ...
Rico-Sanz J - - 1998
1. The main purpose of this study was to evaluate non-invasively with magnetic resonance spectroscopy (1H-MRS) changes in the concentrations of intracellular (IT) and extracellular (between muscle fibres) triglycerides (ET) in skeletal muscles of trained males (age range: 24-38 years) during two standard exercise protocols of alternating velocities. 2. Protocol ...
Williams B D - - 1998
PURPOSE: The purpose of this study was to quantify both alanine and glutamine kinetics during exercise of moderate intensity to determine the sum total of alanine and glutamine flux. METHODS: Tracer methods were used to quantify alanine and glutamine rates of appearance (Ra) in plasma at rest and during 180 ...
Wagner K R - - 1998
OBJECT: The authors previously demonstrated, in a large-animal intracerebral hemorrhage (ICH) model, that markedly edematous ("translucent") white matter regions (> 10% increases in water contents) containing high levels of clot-derived plasma proteins rapidly develop adjacent to hematomas. The goal of the present study was to determine the concentrations of high-energy ...
Ivy J L - - 1998
To maximize glycogen resynthesis after exercise, a carbohydrate supplement in excess of 1.0 g x kg(-1) body wt should be consumed immediately after competition or a training bout. Continuation of supplementation every two hours will maintain a rapid rate of storage up to six hours post exercise. Supplements composed of ...
Kawanaka K - - 1998
Recently (K. Kawanaka, I. Tabata, and M. Higuchi. J. Appl. Physiol. 83: 429-433, 1997), we demonstrated that glucose transport activity after repeated 10-s-long in vitro tetani in rat epitrochlearis (Epi) muscle was negatively correlated with the postcontraction muscle glycogen concentration. Therefore, we examined whether high-intensity intermittent swimming, which depletes muscle ...
Lavoie C - - 1998
The purpose of this study was to investigate the effects of recombinant human erythropoietin (rHuEPO) administration on energy metabolism during exercise. Specifically, the contribution of anaerobic (glycogen) metabolism during exercise was evaluated. Sprague-Dawley rats were randomly assigned to an experimental [rHuEPO] (600 U x kg(-1) of Eprex, every 3 days) ...
Hargreaves M - - 1998
Six men were studied during four 30-s "all-out" exercise bouts on an air-braked cycle ergometer. The first three exercise bouts were separated by 4 min of passive recovery; after the third bout, subjects rested for 4 min, exercised for 30 min at 30-35% peak O2 consumption, and rested for a ...
Snow R J - - 1998
The aim of the present study was to examine the effect of creatine supplementation (CrS) on sprint exercise performance and skeletal muscle anaerobic metabolism during and after sprint exercise. Eight active, untrained men performed a 20-s maximal sprint on an air-braked cycle ergometer after 5 days of CrS [30 g ...
Odland L M - - 1998
The study examined the existence and regulation of fat-carbohydrate interaction during low- and moderate-intensity exercise. Eight males cycled for 10 min at 40% and 60 min at 65% maximal O2 uptake (VO2max) while infused with either Intralipid and heparin (Int) or saline (Con). Before exercise, plasma arterial free fatty acid ...
Boyer-Berri C - - 1998
Myofibrils were prepared from bovine muscles (cutaneous trunci, rectus abdominis, psoas major, and masseter) and compared between different aging periods at 4 degrees C (0, 1, 2, 4, 8, and 16 d). Myofibrils were stained with an antibody directed against a 56-kDa fragment (FE-RE) of titin located in the Z-line ...
Operti M G - - 1998
The activities of adenylosuccinate synthetase, adenylosuccinate lyase, and adenosine monophosphate deaminase were measured in muscle from patients suffering from fatigue and cramps following exercise. Results denote the existence of secondary deficiencies of adenylosuccinate synthetase and/or adenylosuccinate lyase in subjects with congenital or acquired myopathies. They also suggest that searches are ...
Wang L C - - 1998
Short-term (4 days), but not acute, treatment with ginseng saponin (GS, 10 and 20 mg/kg/day) significantly prolonged the aerobic endurance of non-trained rats exercising at approximately 70% VO2max. Compared to the saline controls, GS treatment significantly increased the plasma free fatty acid (FFA) level and maintained plasma glucose level during ...
Febbraio M A - - 1998
To test the hypothesis that an elevation in circulating epinephrine increases intramuscular glycogen utilization, six endurance-trained men performed two 40-min cycling trials at 71 +/- 2% of peak oxygen uptake in 20-22 degrees C conditions. On the first occasion, subjects were infused with saline throughout exercise (Con). One week later, ...
Graham T E - - 1998
In comparison to cardiac tissue, relatively few data are available regarding the concentrations of tricarboxylic acid cycle intermediates (TCAI) and the potential influence of TCAI pool size on the regulation of cycle flux in mammalian skeletal muscle. However, recent human exercise studies have confirmed the fundamental observation made in electrically-stimulated ...
Weltan S M - - 1998
Trained cyclists with low muscle glycogen (LGH; n = 8) or normal glycogen (NGH; n = 5) exercised for 145 min at 70% of maximal oxygen uptake during a hyperglycemic clamp. Respiratory exchange ratio was higher in NGH than LGH, and free fatty acid concentrations were lower in NGH than ...
Weltan S M - - 1998
Euglycemia was maintained in 13 subjects with low muscle glycogen [low glycogen, euglycemic (LGE), n = 8; low glycogen, euglycemic, hyperinsulinemic (LGEI), n = 5] and 6 subjects with normal muscle glycogen (NGE), whereas hyperglycemia was maintained in 8 low muscle glycogen subjects (LGH). All subjects cycled for 145 min ...
Roeykens J - - 1998
The blood lactate (La) - heart rate (HR) relationship assessed during a graded maximal exercise test (GXT) is often used to provide training guidelines to athletes. Glycogen depletion is a condition that is known to influence the La response during a GXT and therefore can bias the interpretation of La ...
Wagenmakers A J - - 1998
Six amino acids are metabolized in resting muscle. They are leucine, isoleucine, valine, asparagine, aspartate, and glutamate. These amino acids provide the amino groups and probably the ammonia required for synthesis of glutamine and alanine, which are released in excessive amounts in the postabsorptive state and during ingestion of a ...
Green H J - - 1997
To examine the effects of a dilutional mediated decrease in arterial O2 content on muscle metabolic and substrate behaviour during exercise, plasma volume was acutely expanded by either 14% (LOW) or 21% (HIGH) using a 6% dextran solution dissolved in saline (Macrodex) and compared with a control (CON) condition. The ...
Halseth A E - - 1997
The aim of this study was to determine how gut and liver protein kinetics adapt to acute exercise in the 18-h-fasted dog (n = 7) and in dogs glycogen depleted by a 42-h fast (n = 8). For this purpose, sampling (artery and portal and hepatic veins) and infusion (vena ...
Brooks G A - - 1997
1. The 'crossover' concept is a model of substrate supply during exercise which makes the following predictions. 2. Lipid is the major fuel (approximately 60%) for non-contracting skeletal muscle and the body at rest. 3. Energy flux, as determined by exercise intensity, is the major factor in determining the balance ...
Bao S - - 1997
We assessed the effects of GLUT4 glucose transporter expression on substrate metabolism and glycogen regulation during exercise. Transgenic mice overexpressing human (h)GLUT4 in muscle and fat (TG) and their wild-type littermates (WT) were studied by indirect calorimetry at rest and during acute treadmill exercise (30 minutes) and recovery (30 minutes). ...
Reynolds A J - - 1997
OBJECTIVE: To evaluate the effect of immediate postexercise carbohydrate supplementation on muscle glycogen (MG) repletion during the first 4 hours of recovery in sled dogs. ANIMALS: 24 Alaskan Huskies. PROCEDURE: Dogs were assigned to 1 of 3 treatment groups, and a muscle biopsy specimen was obtained 1 hour before and ...
Tipton C M - - 1997
1. Since ancient times, athletes have consumed proteins because of the belief they were the necessary substrate for optimal performance. Even though this concept was proven to be incorrect before the beginning of the 19th century, the practice continued until several decades ago. 2. By 1939, careful metabolic investigations on ...
Marx A - - 1997
To evaluate the importance of reactions within the central metabolism under different flux burdens the fluxes within the pentose phosphate pathway (PPP), as well as the other reactions of the central metabolism, were intensively analyzed and quantitated. For this purpose, Corynebacterium glutamicum was grown with [1-(13)C]glucose to metabolic and isotopic ...
Burton R R - - 1997
Adult male chickens adapted to 1.75 or 2.5 G from long term centrifugation, were maximally exercised on an animal treadmill at 1 g (Earth's gravity) and compared with the exercise capacities of control chickens raised at 1 g. The increased-G birds had statistically significantly greater exercise capacities than the controls ...
Bangsbo J - - 1997
The present study examined the role of lactate and glucose as substrates for glyconeogenesis in muscle in recovery from high-intensity exercise in humans. Seven subjects performed approximately 100 min of intense intermittent one-legged knee extensor exercise on two occasions: with [high lactate (HL)] and without [control (C)] intense arm exercise ...
Hawley J A - - 1997
This review suggests that there is little or no effect of elevating pre-exercise muscle glycogen contents above normal resting values on a single exhaustive bout of high-intensity exercise lasting less than 5 minutes. Nor is there any benefit of increasing starting muscle glycogen content on moderate-intensity running or cycling lasting ...
Houghton P E - - 1997
The purpose was to determine if running 30 m/min on a 10 degrees incline, 60 min/day for 5 days/ week altered fetal glycogen storage in prepregnancy trained rats. Animals that exercised for 3 weeks prior to pregnancy either continued the same exercise program until Day 19 of gestation (pregnant running ...
Gibala M J - - 1997
1. This study examined changes in tricarboxylic acid cycle intermediates (TCAIs) in human skeletal muscle during 5 min of dynamic knee extensor exercise (approximately 80% of maximum workload) and following 2 min of recovery. 2. The sum of the seven measured TCAIs (sigma TCAIs) increased from 1.10 +/- 0.08 mmol ...
Figarella-Branger D - - 1997
Exercise intolerance associated with myalgias, muscle cramps or myoglobinuria may be associated with a dystrophinopathy. A search for abnormal dystrophin expression (using immunohistochemistry, immunoblot and DNA analysis) was carried out in a series of 15 patients. They were selected because they presented exercise intolerance, negative biochemical tests (lipid, glycogen and ...
van Zant R S - - 1997
The purpose of this study was to determine the effects of type of preexercise sugar feedings (glucose [GLU] or fructose [FRU]) on muscle glycogen and protein catabolism during prolonged exercise in fed men. Seven men cycled to exhaustion on three different occasions at 70% VO2max, 45 min after ingestion (700 ...
Maughan R J - - 1997
The crucial role of muscle glycogen as a fuel during prolonged exercise is well established, and the effects of acute changes in dietary carbohydrate intake on muscle glycogen content and on endurance capacity are equally well known. More recently, it has been recognized that diet can also affect the performance ...
Dennis S C - - 1997
While the presence of palatable (20 mmol l-1) concentrations of NaCl in drinks containing carbohydrate consumed during intense exercise would not be expected to promote absorption or significantly help maintain fluid balance, there is no doubt that athletes should ingest some from of carbohydrate (other than fructose) during moderate-intensity exercise ...
Adán C - - 1997
The arterio-venous concentrations of oxygen, glucose and lactate, as well as blood flow and muscle levels of lactate, glucose, hexose-phosphates and glycogen of rat hind leg muscle were determined under basal conditions and under mild and intense exercise, as well as during post-exercise recovery. During intense exercise and fatigue glycogen ...
Sibson N R - - 1997
The cerebral tricarboxylic acid (TCA) cycle rate and the rate of glutamine synthesis were measured in rats in vivo under normal physiological and hyperammonemic conditions using 13C NMR spectroscopy. In the hyperammonemic animals, blood ammonia levels were raised from control values of approximately 0.05 mM to approximately 0.35 mM by ...
Glass C - - 1997
This study compared the integrated electromyogram (IEMG), lactate, and ventilatory thresholds under normal glycogen (NG) and depleted glycogen (DG) conditions for the purpose of determining the presence of a possible relationship between neuromuscular, metabolic and respiratory thresholds. Six trained, male cyclists (Age = 24.0 +/- 2.45 yrs, Ht = 1.76 ...
Bräu L - - 1997
The aim of this study was to determine the role of the phosphorylation state of glycogen synthase and glycogen phosphorylase in the regulation of muscle glycogen repletion in fasted animals recovering from high-intensity exercise. Groups of rats were swum to exhaustion and allowed to recover for up to 120 min ...
Abdelmalki A - - 1997
The present study was designed to examine the effects of administration of a GABAergic agonist (Baclofen) on run-time to exhaustion in trained and untrained rats, and on some indicators of fatigue. Run-time to exhaustion on a treadmill set at a speed of 25 m.min-1 was significantly increased in both untrained ...
Hyyppä S - - 1997
OBJECTIVE: To determine glycogen resynthesis rate and changes in plasma metabolite concentrations in horses before and after repeated exercise. ANIMALS: 6 clinically normal Standardbred trotters. PROCEDURE: Horses trotted distances of 3,000, 3,000, and 2,000 m (trial A) and 3 days later, trotted 2,100, 2,100, and 1,600 m (trial B). Horses ...
Parkin J A - - 1997
This study examined the effect of delaying the ingestion of carbohydrate on muscle glycogen storage following prolonged exhaustive exercise. Six endurance trained men cycled on two separate occasions at a workload corresponding to 70% VO2max for 2 h followed by four "all-out" 30-s sprints. Following exercise, subjects were fed five ...
Jackman M L - - 1997
We examined the effect of glycogen availability and branched-chain amino acid (BCAA) supplementation on branched-chain oxoacid dehydrogenase (BCOAD) activity during exercise. Six subjects cycled at approximately 75% of their maximal oxygen uptake to exhaustion on three occasions under different preexercise conditions: 1) low muscle glycogen (LOW), 2) low muscle glycogen ...
Gibala M J - - 1997
Previous studies have used the muscle concentration of citrate + malate + fumarate to estimate tricarboxylic acid (TCA) cycle pool size in humans [e.g., Am. J. Physiol. 259 (Cell Physiol. 28): C834-C841, 1990]. Our purpose was to quantify changes in individual TCA cycle intermediates (TCAI) and total pool size by ...
Nakatani A - - 1997
The purpose of this study was to test the hypothesis that the rate and extent of glycogen supercompensation in skeletal muscle are increased by endurance exercise training. Rats were trained by using a 5-wk-long swimming program in which the duration of swimming was gradually increased to 6 h/day over 3 ...
Grigor P N - - 1997
Eight groups of five farmed red deer were transported by road for three hours, after which they were either slaughtered immediately (TO) or held in lairage for three, six or 18 hours (T3, T6 and T18). Liveweight loss increased with lairage time but hot carcase weight was unaffected. Deer spent ...
< 3 4 5 6 7 8 9 10 11 12 13 >