scholarly journals Redox state changes in human skeletal muscle after isometric contraction.

1986 ◽  
Vol 380 (1) ◽  
pp. 441-451 ◽  
Author(s):  
J Henriksson ◽  
A Katz ◽  
K Sahlin
Keyword(s):  
Skeletal Muscle ◽  
Isometric Contraction ◽  
Human Skeletal Muscle ◽  
Redox State ◽  
State Changes

Failure of glutamate dehydrogenase system to predict oxygenation state of human skeletal muscle

1990 ◽  
Vol 259 (1) ◽  
pp. C26-C28 ◽  
Author(s):  
A. Katz ◽  
M. K. Spencer ◽  
K. Sahlin
Keyword(s):  
Skeletal Muscle ◽  
Metabolic Rate ◽  
Glutamate Dehydrogenase ◽  
Isometric Contraction ◽  
Human Skeletal Muscle ◽  
Redox State ◽  
Mitochondrial Redox State ◽  
Metabolite Ratio ◽  
Tissue Contents ◽  
Total Tissue

In a recent study, the total tissue contents of glutamate (Glu), ammonium (NH+4), and 2-oxoglutarate (2-OG) were used to estimate changes in the mitochondrial redox state ([NAD+]/[NADH]) of contracting skeletal muscle with intact circulation [Am. J. Physiol. 253 (Cell Physiol. 22): C263-C268, 1987]. These metabolites participate in the glutamate dehydrogenase (GDH) reaction, which, based on a number of assumptions, theoretically enables calculation of the mitochondrial redox state as follows (brackets indicate concentrations): [NAD+]/[NADH] = ([NH+4] [2-OG])/[( Glu]Kapp), where Kapp is the apparent equilibrium constant for GDH. The purpose of this study was to determine whether changes in the total tissue contents of Glu, NH+4, and 2-OG could be used to predict a reduction of the mitochondrial redox state in anoxic skeletal muscle. Anoxia was induced in the quadriceps femoris muscle by 10 min of circulatory occlusion (low metabolic rate) and isometric contraction to fatigue (high metabolic rate). The mean (+/- SE) value for the metabolite ratio ([NH+4][2-OG]/[Glu]) at rest was 6 +/- 3 mmol/kg dry wt (x 10(-4]. No significant change occurred after circulatory occlusion (4 +/- 2 x 10(-4); P greater than 0.05), whereas an almost 60-fold increase was observed after isometric contraction (P less than 0.05). Because the muscle was anoxic under both conditions, a significant decrease in the metabolite ratio should have occurred. These data demonstrate that changes in total tissue contents of Glu, NH+4, and 2-OG cannot be used to estimate changes in the redox and oxygenation state of mitochondria in intact human skeletal muscle.

No Change in Insulin Mediators in Human Skeletal Muscle During Isometric Contraction or Recovery

1996 ◽  
Vol 28 (10) ◽  
pp. 545-548 ◽  
Author(s):  
A. Katz ◽  
E. Hultma ◽  
L. Huang ◽  
C. Villar-Palasi ◽  
J. Larner
Keyword(s):  
Skeletal Muscle ◽  
Isometric Contraction ◽  
Human Skeletal Muscle

scholarly journals Redox state and lactate accumulation in human skeletal muscle during dynamic exercise

1987 ◽  
Vol 245 (2) ◽  
pp. 551-556 ◽  
Author(s):  
K Sahlin ◽  
A Katz ◽  
J Henriksson
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Redox State ◽  
Lactate Production ◽  
High Energy ◽  
High Energy Phosphates ◽  
Vo2 Max ◽  
Muscle Lactate ◽  
Lactate Accumulation ◽  
Pyruvate Ratio

The relationship between the redox state and lactate accumulation in contracting human skeletal muscle was investigated. Ten men performed bicycle exercise for 10 min at 40 and 75% of maximal oxygen uptake [VO2(max.)], and to fatigue (4.8 +/- 0.6 min; mean +/- S.E.M.) at 100% VO2(max.). Biopsies from the quadriceps femoris muscle were analysed for NADH, high-energy phosphates and glycolytic intermediates. Muscle NADH was 0.20 +/- 0.02 mmol/kg dry wt. of muscle at rest, and decreased to 0.12 +/- 0.01 (P less than 0.01) after exercise at 40% VO2(max.), but no change occurred in the [lactate]/[pyruvate] ratio. These data, together with previous results on isolated cyanide-poisoned soleus muscle, where NADH increased while [lactate]/[pyruvate] ratio was unchanged [Sahlin & Katz (1986) Biochem. J. 239, 245-248], suggest that the observed changes in muscle NADH occurred within the mitochondria. After exercise at 75 and 100% VO2(max.), muscle NADH increased above the value at rest to 0.27 +/- 0.03 (P less than 0.05) and 0.32 +/- 0.04 (P less than 0.001) mmol/kg respectively. Muscle lactate was unchanged after exercise at 40% VO2(max.), but increased substantially at the higher work loads. At 40% VO2(max.), phosphocreatine decreased by 11% compared with the values at rest, and decreased further at the higher work loads. The decrease in phosphocreatine reflects increased ADP and Pi. It is concluded that muscle NADH decreases during low-intensity exercise, but increases above the value at rest during high-intensity exercise. The increase in muscle NADH is consistent with the hypothesis that the accelerated lactate production during submaximal exercise is due to a limited availability of O2 in the contracting muscle. It is suggested that the increases in NADH, ADP and Pi are metabolic adaptations, which primarily serve to activate the aerobic ATP production, and that the increased anaerobic energy production (phosphocreatine breakdown and lactate formation) is a consequence of these changes.

scholarly journals Contraction-mediated inactivation of glycogen synthase is accompanied by inactivation of glycogen synthase phosphatase in human skeletal muscle

1989 ◽  
Vol 259 (3) ◽  
pp. 901-904 ◽  
Author(s):  
Y Kida ◽  
A Katz ◽  
A D Lee ◽  
D M Mott
Keyword(s):  
Skeletal Muscle ◽  
Isometric Contraction ◽  
Human Skeletal Muscle ◽  
Glycogen Synthase ◽  
Active Form ◽  
Human Muscle ◽  
Maximal Voluntary Force ◽  
Before And After ◽  
Muscle Biopsies

Activities of glycogen synthase (GS) and GS phosphatase were determined on human muscle biopsies before and after isometric contraction at 2/3 maximal voluntary force. Total GS activity did not change during contraction (4.92 +/- 0.70 at rest versus 5.00 +/- 0.42 mmol/min per kg dry wt.; mean +/- S.E.M.), whereas both the active form of GS and the ratio of active form to total GS decreased by approximately 35% (P less than 0.01). GS phosphatase was inactivated in all subjects by an average of 39%, from 5.95 +/- 1.30 to 3.63 +/- 0.97 mmol/min per kg dry wt. (P less than 0.01). It is suggested that at least part of the contraction-induced inactivation of GS is due to an inactivation of GS phosphatase.

scholarly journals Is regulation of proteolysis associated with redox-state changes in rat skeletal muscle?

1980 ◽  
Vol 192 (3) ◽  
pp. 963-966 ◽  
Author(s):  
M E Tischler
Keyword(s):  
Skeletal Muscle ◽  
Oxidation State ◽  
Redox State ◽  
Proteinase Activity ◽  
Rat Skeletal Muscle ◽  
Direct Inhibition ◽  
State Changes ◽  
Isolated Rat

In isolated rat diaphragms, only those substrates that increased the tissue NADH/NAD+ ratio lowered the rate of proteolysis. However, direct inhibition of proteinase activity by leupeptin promoted oxidation of the NAD couple of the muscles. These results suggest that changes in muscle reduction-oxidation state may be important in the regulation of proteolysis.

Dependence of the dynamic speckle field spectral parameters on the force of isometric contraction of human skeletal muscle

2001 ◽  
Author(s):  
Sergei C. Dick ◽  
Leonid V. Tanin ◽  
Lyudmila A. Vasilevskaya ◽  
P. N. Bagrov ◽  
T. D. Lebedeva
Keyword(s):  
Skeletal Muscle ◽  
Isometric Contraction ◽  
Human Skeletal Muscle ◽  
Spectral Parameters ◽  
Speckle Field ◽  
Dynamic Speckle
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