Journal ArticleDOI
Effect of oxygen tension on cellular energetics
TLDR
It is concluded that limited oxygen supply affects cellular metabolism at much higher concentrations than the P50 value for the oxygen dependence of respiration, but the respiratory rate remains relatively unchanged due to compensatory changes in the [ATP]/[ADP] X [Pi] and progressive reduction of cytochrome c.Abstract:
Simultaneous measurements of the mitochondrial [NAD+]/[NADH], the cytoplasmic [ATP]/[ADP] x [Pi], and the respiratory rate were carried out in suspensions of cultured kidney cells in a range of defined oxygen tensions. The results show that as the extracellular oxygen concentration falls there is a decrease in the respiratory rate, which is accompanied by a decrease in the [ATP]/[ADP] and a progressive reduction of cytochrome c. Even at low O2 tensions the mitochondrial respiratory chain between the NAD couple and cytochrome c remains at near equilibrium with the ATP synthesizing reactions. It is concluded that limited oxygen supply affects cellular metabolism at much higher concentrations than the P50 value for the oxygen dependence of respiration, but the respiratory rate remains relatively unchanged due to compensatory changes in the [ATP]/[ADP] X [Pi] and progressive reduction of cytochrome c. These metabolic changes may form a basis for the phenomenon of tissue oxygen sensing at near physiological oxygen tensions.read more
Citations
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Myoglobin O2 desaturation during exercise. Evidence of limited O2 transport.
TL;DR: Large differences in PO2 between blood and intracellular tissue have been demonstrated in intact normal human muscle and are found over a wide range of exercise intensities, consistent with an O2 diffusion limitation across the 1-5-microns path-length from red cell to the sarcolemma that plays a role in determining maximal muscle O2 uptake in normal humans.
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Skeletal muscle dysfunction in chronic obstructive pulmonary disease.
TL;DR: Testosterone supplementation has been shown to increase muscle mass and strength in both hypogonadal and eugonadal healthy men as mentioned in this paper, and low-dose testosterone supplementation is being considered for use in postmenopausal women.
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Introduction to Functional Magnetic Resonance Imaging: Principles and Techniques
TL;DR: The nature of the BOLD effect, Mapping brain activation with BOLD-fMRI, and Efficient design of BOLD experiments are described.
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Regulation of cellular energy metabolism.
Maria Erecińska,David F. Wilson +1 more
TL;DR: Variations in the cellular concentrations of ATP, ADP, and inorganic phosphate provide a very sensitive means through which homeostatic mechanisms can regulate energy production.
Journal ArticleDOI
The oxygen dependence of mitochondrial oxidative phosphorylation measured by a new optical method for measuring oxygen concentration.
TL;DR: The oxygen dependence of mitochondrial oxidative phosphorylation is such that mitochondria could function in their proposed role of tissue oxygen sensors for regulation of such diverse functions as local blood flow and electrical activity in the carotid body.
References
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Enzymic determination of d(−)-β-hydroxybutyric acid and acetoacetic acid in blood
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Polyoma transformation of hamster cell clones--an investigation of genetic factors affecting cell competence.
Ian Macpherson,Michael Stoker +1 more
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