Search Results
Results 351 - 400 of 805
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Schuback K - - 1999
The aim was to study metabolic response and locomotion pattern in Standardbred trotters during incremental treadmill exercise performed by increasing speed by 1 m/s in 1 min steps (start 7 m/s) until the onset of fatigue. The test protocol included determination of oxygen uptake, heart rate (HR), stride length (SL) ...
MacLaren D P - - 1999
We studied the effects of maintained hyperglycemia (12 mmol/l) on endurance exercise to determine the hormonal and metabolic responses, the maximal rate of glucose infusion (i.e., utilization), and the effects on muscle glycogen stores. Eight men undertook two trials during which they exercised on a cycle ergometer at an intensity ...
Greiwe J S - - 1999
The purpose of this investigation was to determine whether endurance exercise training increases the ability of human skeletal muscle to accumulate glycogen after exercise. Subjects (4 women and 2 men, 31 +/- 8 yr old) performed high-intensity stationary cycling 3 days/wk and continuous running 3 days/wk for 10 wk. Muscle ...
Toderico, Benjamin J.
The existence of a glycogen-sarcoplasmic reticulum has been demonstrated by a number of researchers. This complex is suspected to participate in the calcium uptake activities of the sarcoplasmic reticulum (SR). Removal of glycogen particles associated with this complex may alter the calcium handling abilities of the SR. This experiment sought ...
Anthony J C - - 1999
This study was designed to determine the ability of leucine to enhance muscle recovery after exercise. Male rats (200 g) were divided into five groups: sedentary, food-deprived (SF); exercised, food-deprived (EF); exercised, fed a carbohydrate meal (EC); exercised, fed a leucine meal (EL); and exercised, fed a combination of carbohydrate ...
MacDougall J D - - 1999
Biopsies (biceps) were examined in 8 bodybuilders across a typical arm-curl training session (80% 1-RM). [PCr] and [glycogen] decreased 62 and 12% after 1 set (n = 4), and 50 and 24% after 3 sets (n = 4). [Lactate] was 91 and 118 mmol &times kg-1, respectively, after 1 and ...
Bowtell J L - - 1999
The purpose of this study was to determine the efficacy of glutamine in promoting whole body carbohydrate storage and muscle glycogen resynthesis during recovery from exhaustive exercise. Postabsorptive subjects completed a glycogen-depleting exercise protocol, then consumed 330 ml of one of three drinks, 18.5% (wt/vol) glucose polymer solution, 8 g ...
Goreham C - - 1999
To investigate the hypothesis that changes in muscle submaximal exercise metabolism would occur as a result of fiber hypertrophy, induced by high-resistance training (HRT), active but untrained males (age 20 +/- 0.7 yr; mean +/- SE) performed lower-limb weight training 3 days/wk for 12 wk using three sets of 6-8 ...
Jannaschk D - - 1999
Experimental and model studies have been performed to characterise the effects of Cu2+ on the activities of individual glycolytic enzymes and on the flux and internal metabolite concentrations of the upper part of glycolysis in mouse muscle extracts. Cu2+ significantly inhibited the triosephosphate production from glucose with an IC50 of ...
Sneddon LU - - 1999
The energetic consequences of fighting, which may depend on environmental conditions, can be an important factor shaping contest strategy and duration. Energy expenditure may be costly to fitness because it depletes reserves that could otherwise have been allocated to reproduction, and metabolites are produced that may constrain subsequent activities. We ...
Kuo C H - - 1999
The purpose of this study was to determine the time course of GLUT4 protein accumulation following an exercise-carbohydrate supplementation regimen, and to evaluate the effect of this regimen on GLUT4 mRNA regulation. Rats were exercised by swimming and intubated with 1 mL of a 50% glucose solution immediately post-exercise. Exercise ...
Blomstrand E - - 1999
1. Eight subjects performed two-legged exercise, one leg with low and the other with normal muscle glycogen content. The purpose was to study the effect of low initial muscle glycogen content on the metabolic response during 1 h of exercise and 2 h of recovery. This model allows direct comparison ...
Tate C A - - 1998
We examined the evidence for greater fat utilization by women during exercise and the potential gender differences in specific cellular processes. Results from well-controlled studies show that, compared to men, women oxidize more fat during submaximal exercise, resulting in the relative sparing of muscle glycogen. Mature female rats use less ...
Wang Y - - 1998
Electrical stimulation of a trout saline-perfused trunk preparation resulted in metabolic and respiratory responses comparable to those occurring after exhaustive exercise in vivo. Recovery of intracellular acid-base status and glycogen resynthesis were faster than in vivo. Intracellular carbonic anhydrase (ICF CA) blockade elevated intracellular PCO2 relative to untreated postexercise controls, ...
Azevedo J L JL - - 1998
The present study was undertaken to determine the effects of endurance training on glycogen kinetics during exercise. A new model describing glycogen kinetics was applied to quantitate the rates of synthesis and degradation of glycogen. Trained and untrained rats were infused with a 25% glucose solution with 6-3H-glucose and U-14C-lactate ...
Borba-Murad G R - - 1998
The participation of hepatic glycogenolysis and gluconeogenesis to the glycemic changes promoted by exercise was investigated. For this purpose, we employed swimming rats (2.5% body weight extra load attached to the tail, at 24 degrees C) using a favorable condition to measure hepatic glycogenolysis (fed rats) and a favorable condition ...
Fraser H - - 1998
Glycogen and its turnover are important components of myocardial glucose metabolism that significantly impact on postischemic recovery. We developed a method to measure glycogen turnover (rates of glycogen synthesis and degradation) in isolated working rat hearts using [3H]- and [14C]glucose. In aerobic hearts perfused with 11 mM glucose, 1.2 mM ...
Rasmussen B B - - 1998
Previous studies have demonstrated that oxygen consumption and fat oxidation remain elevated in the postexercise period. The purpose of this study was to determine whether malonyl-CoA, an inhibitor of fatty acid oxidation, remains depressed in muscle after exercise. Rats were sprinted for 5 min (40 m/min, 5% grade) or run ...
Halseth A E - - 1998
The goal of this study was to determine how liver glutamine (Gln) metabolism adapts to acute exercise in the 18-h-fasted dogs (n = 7) and in dogs that were glycogen depleted by a 42-h fast (n = 8). For this purpose, sampling (carotid artery, portal vein, and hepatic vein) and ...
Holloszy J O - - 1998
The rate of carbohydrate utilization during prolonged, strenuous exercise is closely geared to the energy needs of the working muscles. In contrast, fat utilization during exercise is not tightly regulated, as there are no mechanisms for closely matching availability and metabolism of fatty acids to the rate of energy expenditure. ...
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 ...
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