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Results 401 - 450 of 761
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Sancho E - - 1996
The present communication deals with the effect of fenitrothion (0.04 ppm) on the carbohydrate metabolism of the european eel Anguilla anguilla and its recovery from intoxication. Analysis of various parameters such as glycogen, lactate and glucose was made on different eel tissues after 2, 8, 12, 24, 32, 48, 56, ...
Dyck D J - - 1996
This study examined muscle glycogenolysis and the regulation of glycogen phosphorylase (Phos) activity during 15 min of cycling at 85% of maximal O2 consumption (VO2max) in control and high free fatty acid (FFA; Intralipid-heparin) conditions in 11 subjects. Muscle biopsies were sampled at rest and 1, 5, and 15 min ...
Müller M J - - 1996
The liver is central to the metabolic response to exercise but measurements of effects of reduced liver function on the physiological adaptation to exercise are scarce. We investigated metabolic, endocrine, pulmonary and haemodynamic responses to exercise in 15 healthy untrained controls (Co) and in 30 subjects with reduced liver function ...
Kudelska G - - 1996
The aim of the present study was to examine the rate of glycogen mobilization during exercise and the rate of the postexercise glycogen replenishment in different muscle types [white (WG), and red (RG) gastrocnemius, soleus (S) and diaphragm (D)] in rats treated with triiodothyronine (T3, group T). Rats of the ...
Oöpik V - - 1996
The aim of the present study was to assess the effect of creatinine administration on urea metabolism in sedentary and exercised Wistar rats and also on the rate of glycogen resynthesis in the liver and skeletal muscle of endurance-trained animals after exhausting exercise. Creatine treatment for 7 days significantly increased ...
Shulman R G - - 1996
Natural-abundance 13C nuclear magnetic resonance (NMR) spectroscopy is a noninvasive technique that enables in vivo assessments of muscle and/or liver glycogen concentrations. When directly compared with the traditional needle biopsy technique, NMR was found to be more precise. Over the last several years, we have developed and used 13C-NMR to ...
Peters T J - - 1996
Ethanol is recognized to affect adversely carbohydrate metabolism in skeletal muscle. This paper seeks to establish whether ethanol acutely impairs glycogen repletion during recovery from high intensity short duration exercise in the rat. High intensity exercise caused the massive mobilization of glycogen stores in muscles rich in type IIa and ...
Hargreaves M - - 1996
Five trained men were studied during 2 h of cycling exercise at 67% peak oxygen uptake at 20-22 degrees C to examine the effect of fluid ingestion on muscle metabolism. On one occasion, the subjects completed this exercise without fluid ingestion (NF) while on the other they ingested a volume ...
Schneiter P - - 1995
To determine the metabolic effects of a single bout of exercise performed after a meal or in the fasting state, nine healthy subjects were studied over two 8-h periods during which net substrate oxidation was monitored by indirect calorimetry. On one occasion, exercise was performed 90 min after ingestion of ...
van Hall G - - 1995
1. The influence of pre-exercise muscle glycogen content on ammonia production, adenine nucleotide breakdown and amino acid metabolism was investigated during prolonged exercise in six subjects having one leg with a normal and one leg with a low muscle glycogen content. One-leg knee-extensor exercise was performed for 90 min, at ...
Mäkelä T P - - 1995
Freshwater mussels Anodanta anatina and Pseudanodonta complanata were exposed to (14C)-pentachlorophenol. The wet weight based bioconcentration factor (BCF = activity in animal per activity in water) at steady state varied from 80 to 120 for A. anatina and from 61 to 85 for P. complanata. The species did not differ ...
Green H J - - 1995
The objective of this study was to test the hypothesis that the increased glycogen concentration found in the working muscles following short-term training would result in an increase in endurance performance. Endurance performance was examined in 8 active but untrained males who cycled until fatigue at 65% VO2max prior to ...
Vandenberghe K - - 1995
This study examined the effect of glycogen supercompensation on glycogen breakdown, muscle and blood lactate accumulation, blood-pH, and performance during short-term high-intensity exercise. Young healthy volunteers performed two supramaximal (125% of VO2max) exercise tests on a bicycle ergometer, either for 1 min 45 s (protocol 1; N = 18) or ...
McAllister R M - - 1995
Both hypo- and hyperthyroidism are characterised by exercise intolerance. In hypothyroidism, inadequate cardiovascular support appears to be the principal factor involved. Insufficient skeletal muscle blood flow compromises exercise capacity via reduced oxygen delivery, and endurance through decreased delivery of blood-borne substrates. The latter effect results in increased dependence on intramuscular ...
Sherman W M - - 1995
Physical activity in the form of exercise requires the metabolism of bodily fuel reserves to provide energy for muscle contraction. Under normal circumstances, very little protein is metabolized to provide the energy for muscle contraction. At rest and at low exercise intensities, the metabolism of fat provides a considerable proportion ...
Sahlin K - - 1995
1. The importance of the level of tricarboxylic acid cycle intermediates (malate, citrate and fumarate) for energy transduction during exercise has been investigated in six healthy subjects and in two patients with muscle phosphorylase deficiency (McArdle's disease). 2. Healthy subjects cycled for 10 min at low (50 W), moderate [130 ...
Putman C T - - 1995
Pyruvate dehydrogenase activity (PDHa), acetyl group, and citrate accumulation were examined in human skeletal muscle at rest and during cycling exercise while acetate was infused. Eight subjects received 400 mmol of sodium acetate (Ace) at a constant rate during 20 min of rest, 5 min of cycling at 40% maximal ...
Coyle E F - - 1995
When people walk at low intensity after fasting, the energy needed is provided mostly by oxidation of plasma fatty acids. As exercise intensity increases (eg, to moderate running), plasma fatty acid turnover does not increase and the additional energy is obtained by utilization of muscle glycogen, blood glucose, and intramuscular ...
Tarnopolsky M A - - 1995
During endurance exercise at approximately 65% maximal O2 consumption, women oxidize more lipids, and therefore decrease carbohydrate and protein oxidation, compared with men (L.J. Tarnopolsky, M.A. Tarnopolsky, S.A. Atkinson, and J.D. MacDougall. J. Appl. Physiol. 68: 302-308, 1990; S.M. Phillips, S.A. Atkinson, M.A. Tarnopolsky, and J.D. MacDougall. J. Appl. Physiol. ...
Kim C K - - 1995
Muscle glycogen depletion pattern and metabolic responses during voluntary (VOL) and functional electrical stimulated (FES) dynamic knee-extensor exercise with one leg were evaluated. Seven healthy men exercised for 60 minutes at 30 W with an pulmonary oxygen uptake of 0.8 and 1.01 min-1, and respiratory exchange ratios of 0.90 and ...
Asp S - - 1995
1. Eccentric exercise causes impaired postexercise glycogen resynthesis. To study whether changes in muscle concentration of the glucose transporter (GLUT4) protein might be involved, seven healthy young men performed one-legged eccentric exercise by resisting knee flexion enforced by a motor-driven device. 2. The GLUT4 protein concentration in the exercised and ...
Lancha A H AH - - 1995
The present study examined the effect of diet supplementation of oxaloacetate precursors (aspartate and asparagine) and carnitine on muscle metabolism and exercise endurance. The results suggest that the diet supplementation increased the capacity of the muscle to utilize FFA and spare glycogen. Time to exhaustion was about 40% longer in ...
Jansson I - - 1995
At low levels of phenobarbital induction two forms of isoenzyme 2 (LM2; CYP2B4) were obtained during purification of cytochrome P450 from rabbit liver microsomes. At high levels of induction only one form (LM2A) was present. Although the two purified forms (LM2A and LM2B) were very similar they differed in: (a) ...
Litvinova L - - 1995
In Wistar rats after swimming for 3 h, the glycogen level remained low in the liver during a period of 7 h. When sucrose was administered immediately after exercise, the liver glycogen content increased rapidly. From the 3rd to the 5th postexercise hour a secondary reduction was observed in hepatic ...
Hargreaves M - - 1995
To examine the effects of alterations in preexercise muscle glycogen availability on glycogenolysis and glucose uptake during exercise, 12 active but untrained men [22.8 +/- 1.6 (SE) yr, 71.7 +/- 2.0 kg, peak pulmonary oxygen uptake 3.85 +/- 0.16 l/min] were studied during 40 min of cycle ergometer exercise at ...
van Baak M A - - 1995
Twelve healthy male volunteers cycled to exhaustion at a workload corresponding to 70% of maximal aerobic power after administration of 80 mg of the beta 1+2-adrenoceptor antagonist propranolol and after administration of placebo by mouth. Exercise times until exhaustion were 39 +/- 7 and 86 +/- 7 min in the ...
Dossett-Mercer J - - 1994
To examine the effect of exercise on sarcoplasmic reticulum function in muscle tissue of different fibre composition, adult male Wistar rats weighing 388 +/- 23 g (x +/- SE) ran intermittently on a treadmill until fatigue. Fatigue was induced by 15-20 min of running performed at 52 m/min on an ...
Vukovich M D - - 1994
This study investigated the effects of L-carnitine supplementation on muscle carnitine and glycogen content during submaximal exercise (EX). Triglycerides were evaluated by a fat feeding (90 g fat) and 3 h later subjects cycled for 60 min at 70% VO2max (CON). Muscle biopsies were obtained preexercise and after 30 and ...
Price T B TB Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT - - 1994
To determine whether glycogen turnover occurs during prolonged low-intensity exercise, five subjects performed plantar flexion of the right leg at 15% MVC for 5 h. At rest and during the initial 2.5 h of exercise gastrocnemius glycogen was monitored in both legs with natural abundance 13C NMR. At 2.5 h ...
Greenhaff P L - - 1994
1. Muscle biopsy samples were obtained from the vastus lateralis of six healthy volunteers before and after 30 s of treadmill sprinting. A portion of each biopsy sample was used for mixed-fibre metabolite analysis. Single fibres were dissected from the remaining portion of each biopsy and were used for ATP, ...
Coleman E - - 1994
Athletes often train or compete in athletic events that significantly reduce muscle and liver glycogen reserves. Carbohydrate ingestion before or during endurance exercise enhances performance by maintaining blood glucose levels and carbohydrate utilization. Also, an adequate intake of carbohydrate following endurance exercise helps to restore muscle and liver glycogen. This ...
Braiden R W - - 1994
Because cocaine causes a rapid sympathetic response and central euphoria, we tested whether it would improve endurance or alter carbohydrate metabolism during high-intensity activity. Thirty male rats (10 animals/group) were injected intraperitoneally with either saline (S) or one of two doses of cocaine-HCl (12.5 (C-1) or 20.0 (C-2) mg.kg-1 b.w.). ...
Anatskaya O V - - 1994
Two alternate hypotheses explaining the causes of mammalian liver polyploidy have been tested by means of statistical analysis of more than 30 placental species. According to the first (general) hypothesis, the omission of mitosis is beneficial in rapidly growing and differentiating tissues that should early perform their specialized functions (economy ...
Magnusson I - - 1994
Whether liver glycogen synthesis and breakdown occur simultaneously during net glycogen synthesis was assessed in fed and fasted healthy humans. The peak intensity of the carbon-1 (C1) resonance of the glycosyl units of glycogen was monitored with 13C nuclear magnetic resonance spectroscopy during [1-13C]glucose infusion followed by unlabeled glucose infusion. ...
Sumida K D - - 1994
The effects of endurance training (running 30 m/min, 10% grade for 90 min, 5 days/wk for 12 wk) on skeletal muscle glucose uptake during steady-state exercise (running 20 m/min) were studied in fed rats. A bolus injection of 2-[1,2-3H]deoxyglucose was administered to assess the glucose metabolic index (R'g), an indicator ...
Schneiter P - - 1994
In vivo glycogen kinetics was estimated with the simultaneous use of indirect calorimetry and tracer technology in healthy humans during 24-h periods with low or moderate physical activity (1 or 3 exercise sessions each day). Two 13C-carbohydrates meals were administered at 9.30 a.m. and 1.30 p.m., and one 12C-carbohydrates meal ...
Green S - - 1994
The degree to which the y-intercept (Y-int) of the linear regression of maximal work output on exercise duration represented anaerobic capacity was determined in ten well-trained male cyclists [peak oxygen uptake (VO2peak) = 69.8 (SD 4.2) ml.kg-1.min-1]. Each cyclist performed three exhausting cycle sessions on separate occasions; the mean exercise ...
Hellsten-Westing Y - - 1994
The exchange of purines in liver and active skeletal muscle with short-term exhaustive exercise was investigated. Eight male subjects performed two similar 10-min bouts of exhaustive supine cycling, separated by 75 min of rest. Immediately after termination of the second bout, a tourniquet was applied to the upper part of ...
Varnier M - - 1994
The aim of this study was to investigate whether, when muscle glycogen is reduced, a pre-exercise infusion of branched-chain amino acids (BCAA) modifies exercise performance or the metabolic and respiratory responses to incremental exercise. Six moderately trained volunteers took part in the following protocol on two occasions. On day 1, ...
Price T B - - 1994
To study the effects of glycogen depletion and insulin concentration on glycogen synthesis, gastrocnemius glycogen was measured with 13C-nuclear magnetic resonance at 4.7 T after exercise. Subjects performed single-leg toe raises to deplete gastrocnemius glycogen to 75, 50, or 25% of resting concentration (protocol I). Insulin dependence of glycogen synthesis ...
Bloch G G Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut - - 1994
Time courses of the glycogen synthesis rate and of the glucose 6-phosphate (G-6-P) concentration after an electrically induced exercise were followed in the anesthetized rat gastrocnemius by in vivo 13C and 31P nuclear magnetic resonance (NMR) spectroscopy, respectively. The ratio of glycogen synthase I to glycogen synthase I and D ...
Dyck D J - - 1993
Six male subjects received either a saline (control) or Intralipid infusion during 30 min rest and 15 min cycling at 85% maximal O2 uptake (VO2max) to examine the regulation of fat-carbohydrate interaction (glucose-fatty acid cycle) in skeletal muscle. Muscle biopsies were sampled immediately before and at 3 and 15 min ...
Burge C M - - 1993
Eight international class lightweight rowers were examined to determine the efficacy of rehydrating with water following 24 h of dehydration on body fluid balance, metabolic function, and rowing performance. The rowers performed a maximal rowing trial on a Gjessing rowing ergometer (4200 revs, 3-kg resistance) while euhydrated (ET) and following ...
Yoshino M - - 1993
1. Role of NADP-glutamate dehydrogenase in the depletion of citrate was analyzed using permeabilized yeast cells. 2. Citrate was converted to 2-oxoglutarate, which was then metabolized to glutamate by NADP-glutamate dehydrogenase in the presence of ammonium ion. 3. Formation of 2-oxoglutarate plus glutamate was in good agreement with the concentration ...
Mehrani H - - 1993
To analyze the mechanisms of glycogen phosphorylase control in organs of the rainbow trout Oncorhynchus mykiss, activities of glycogen phosphorylase kinase (GPK) and cAMP-dependent protein kinase (PKA), as well as levels of cAMP, were quantified. The complete cascade for activating glycogen phosphorylase was present in trout organs and all components ...
Craig B W - - 1993
Athletic competition requires great energy expenditure and the ability to maintain performance depends on an adequate supply of metabolic fuels, which has led to the use of dietary supplements. Much of the data concerning fructose supplementation is contradictory in nature, but it shows that fructose feeding before or during exercise ...
Putman C T - - 1993
Pyruvate dehydrogenase activity (PDHa) and acetyl group accumulation were examined in human skeletal muscle at rest and during exercise after different diets. Five males cycled at 75% of maximal O2 uptake (VO2 max) to exhaustion after consuming a low-carbohydrate diet (LCD) for 3 days and again 1-2 wk later for ...
Marchini J S - - 1993
The in vivo rate of conversion of phenylalanine to tyrosine (PheOH) can be estimated using combinations of stable isotope-labeled phenylalanine and tyrosine. We have compared in four healthy adult men the rates of phenylalanine conversion to tyrosine based on the following pairs of primed, continuous tracer infusions administered simultaneously: (1) ...
Zinker B A - - 1993
We hypothesized that augmented responses of glucoregulatory hormones in iron deficiency would enhance liver and muscle glycogenolysis, leading to increased gluconeogenic precursor (lactate) supply and upregulation of hepatic gluconeogenesis. Female weanling rats were randomly placed on either a mildly iron-deficient (-Fe; 15 mg Fe/kg diet) or an iron-sufficient (+Fe; 50 ...
Aragón-Vargas L F - - 1993
Early studies agree that fasting is detrimental to overall physical performance and to endurance performance in humans; however, a study in rats reported an ergogenic effect where time to exhaustion was increased by a glycogen-sparing effect of elevated free fatty acids in blood resulting from a 24-hour fast. Later studies ...
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