Creatine Phosphate

Lamprecht, Walther; Stein, Philipp

doi:10.1016/b978-0-12-395630-9.50121-3

Cited by 31 publications

(7 citation statements)

References 17 publications

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“…Lactate was assayed by the method of Hohorst [5]. ATP and creatine phosphate were measured by the method of Lamprecht and Stein [6]. Orthophosphate was measured using an enzymatic method similar to that reported by Guynn et al [7].…”

Section: Methodsmentioning

confidence: 99%

The Purine‐Nucleotide Cycle

Aragón

Lowenstein

1980

European Journal of Biochemistry

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The contents of citric acid cycle compounds were measured in rat hind limb muscle in situ during rest, exercise, and recovery from exercise. The following changes in citric acid cycle intermediates were observed during exercise for 15 min. The contents of fumarate and malate increased fourfold over resting values. The contents of citrate, isocitrate, and succinate rose 68 'I<, 48 and 87 "' , respectively, but the increase in these intermediates was delayed relative to the increase in fumarate and malate. The content of 2-oxoglutarate did not change significantly. The content of oxaloacetate increased from less than 1 nmol/g dry weight in resting muscle to 8 nmol/g dry weight during exercise. The orthophosphate content doubled. The sum of the contents of citric acid cycle intermediates doubled. The ratios of the contents of malate/fumarate and citrate/isocitrate remained constant. The constancy of the citrate/isocitrate ratio indicates that the concentration of intracellular free Mg2+ is not affected by exercise. All metabolite levels returned to resting values during recovery. Comparison of these data with the rate of operation of the purine nucleotide cycle leads us to conclude that the increase in citric acid cycle intermediates can be accounted for by the operation of the purine nucleotide cycle.The rate of operation of the purine nucleotide cycle in skeletal muscle increases during exercise and recovery following exercise [l, 21. The cycle catalyzes the net reaction : aspartate + GTP + H20 + NH3 + fumarate + G D P + Pi. We now show that the total level of citric acid cycle intermediates in rat skeletal muscle rises by a factor of two during exercise. The changes in citric acid cycle intermediates are compared with the rate of formation of IMP in the absence and presence of hadacidin, an inhibitor of adenylosuccinate synthetase. On the basis of this comparison it is concluded that the operation of the purine nucleotide cycle is sufficient to account for the observed increases in citric acid cycle intermediates in skeletal muscle. Other possible reactions for replenishing or increasing citric acid cycle intermediates are considered in the Discussion.ions participate in the reactions of the citric acid and the purine nucleotide cycles and they exert direct and indirect effects on adenylate deaminase [3]. Determinations of the contents of these substances in skeletal muscle during rest, exercise, and recovery from exercise are also presented. Orthophosphate and Mg2 MATERIALS AND METHODSMale rats of the Sprague-Dawley strain were obtained from Charles River Breeding Laboratories (Wilmington, MA). The animals received food and water ad libitum, and weighed 175-200 g at the time of use.Rats were anaesthetized by intraperitoneal injection of sodium pentobarbital (5 mg/100 g body weight) and the skin from the right hind leg was removed. The sciatic nerve was exposed and a Dastre's electrode (Palmer Co., London, UK) was attached around the nerve in its gluteal course. The leg was fixed to a platform at the ankle with ...

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Section: Methodsmentioning

confidence: 99%

The Purine‐Nucleotide Cycle

Aragón

Lowenstein

1980

European Journal of Biochemistry

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“…Dilutions of reagents and volumes mixed were so arranged that 100 #l. of the final extract was equivalent to 1 mg of the original muscle powder. All the glycolytic metabolites and cofactors were assayed using enzymatic methods based on those by Slein (1963), Bergmeyer & Klotzsch (1963), Bucher & Hohorst (1963), Hohorst (1963a, b), Bernt, Bergmeyer & Mollering (1963), Adam (1963), Lamprecht & Stein (1963) and Lowry, Passoneeau, Hasselberger & Schultz (1964). Oxidation and reduction of pyridine nucleotides was followed at 334 m, using an Eppendorf spectrometer (model 1101), fitted with a mercury lamp, photomultiplier and connected to an Eppendorf 4412 recorder.…”

Section: Methodsmentioning

confidence: 99%

Effect of temperature on muscle energy metabolism and endurance during successive isometric contractions, sustained to fatigue, of the quadriceps muscle in man

Edwards¹,

Harris²,

Hultman³

et al. 1972

The Journal of Physiology

232

169

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SUBMARY1. The effects of altered tissue temperature on muscle metabolism during successive isometric contractions, sustained to fatigue, have been studied in the quadriceps muscle of man by combining biochemical analyses of metabolites in needle biopsy samples with measurements of endurance time with a force of 2/3 maximum voluntary contraction. Fatigue and recovery were observed repeatedly in a series of seven contractions at intervals of 20 sec, following immersion of the test leg in water at 12, 26 or 440 C for 45 min. Muscle temperatures corresponding to these water temperatures were 22-5, 32-6 and 38 6°C respectively.2. Increased levels of several glycolytic intermediates at rest in the heated muscle suggested an increased rate of glycolysis. ATP and phosphoryl creatine were lower at the end of the first contraction and the calculated rate of ATP utilization (including the contribution from anaerobic glycolysis) was highest in the heated nuscle.3. Significantly shorter endurance times were found for the heated muscle. These could not be attributed to depletion of local energy resources in muscle. Fatigue may be due to a reduction in the rate of regeneration of ATP from anaerobic glycolysis below that needed to maintain the contraction force. Lower values for the ratio of fructose 1,6-diphosphate: fructose 6-phosphate at the end of contractions, particularly at the highest temperature, are compatible with the hypothesis that there is partial inhibition of the rate controlling enzyme phosphofructokinase, possibly due to the accumulation of hydrogen ions in muscle.

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“…Adenosine triphosphate (ATP) and creatine phosphate (CP) were determined by the methods of Lamprecht, Stein, and Trautschold (26,27). Lactate and pyruvate were measured by the methods of Hohorst (28) and Segal et al (29).…”

Section: Methodsmentioning

confidence: 99%

Protective Role of Increased Myocardial Glycogen Stores in Cardiac Anoxia in the Rat

Scheuer

Stezoski

1970

Circulation Research

139

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To determine whether increased glycogen stores might protect the heart against anoxia, experiments were performed in the isolated perfused rat heart. Marked differences in cardiac glycogen were produced by comparing hearts from rats previously treated with reserpine with hearts from control rats. Lesser differences in cardiac glycogen were produced in hearts by perfusing them for IS minutes without glucose (0 HIM glucose) or with 20 HIM glucose. Both groups were then studied during a 5-minute anoxic cycle with 5 DIM glucose as the exogenous substrate. Hearts from the reserpine-treated rats had higher left ventricular pressures, maximal rate of left ventricular pressure rise, and lactate output after 2 minutes of anoxia than the hearts from control rats. Similar but less marked mechanical differences were observed between 0 mM glucose and 20 mM glucose hearts. The mechanical differences during anoxia between the two groups were not abolished by simultaneous L-norepinephrine administration. Hearts with greater initial glycogen stores had higher glycogenolytic rates, and proportionately more lactate was produced from glycogen than from glucose. Thus, anaerobic ATP production per mole of hexose was greater in hearts with higher glycogen stores. Calculated ATP production was also greater in hearts from the reserpine-treated rats than in those from control animals.These studies demonstrate that both marked and minor elevations in cardiac glycogen are associated with greater glycolytic reserve and improved mechanical resistance to anoxia. This appears to be mainly due to enhanced glycogenolysis and anaerobic ATP production.

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Creatine Phosphate

Cited by 31 publications

References 17 publications

The Purine‐Nucleotide Cycle

The Purine‐Nucleotide Cycle

Effect of temperature on muscle energy metabolism and endurance during successive isometric contractions, sustained to fatigue, of the quadriceps muscle in man

Protective Role of Increased Myocardial Glycogen Stores in Cardiac Anoxia in the Rat

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