scholarly journals Liver oxygen consumption of cold- and warm-acclimated rats and factors regulating liver oxidative metabolism

1966 ◽  
Vol 14 (1-4) ◽  
pp. 528-540 ◽  
Author(s):  
Eugen Zeisberger
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Metabolism

scholarly journals SELECTIVE INHIBITION BY PREPARATIONS OF STREPTOCOCCAL FILTRATES OF THE OXIDATIVE METABOLISM OF MITOCHONDRIA PROCURED FROM RABBIT MYOCARDIUM

1956 ◽  
Vol 104 (4) ◽  
pp. 577-587 ◽  
Author(s):  
Arthur S. Carlson ◽  
Aaron Kellner ◽  
Alan W. Bernheimer
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Metabolism ◽  
Selective Inhibition ◽  
Sharp Reduction ◽  
Complete Cessation ◽  
Heat Labile ◽  
Streptolysin O ◽  
Selective Interference ◽  
Rabbit Myocardium

When solutions of streptolysin O were added to Warburg flasks containing, among other constituents, suspensions of mitochondria from the myocardium of rabbits and citrate, fumarate, or alpha-ketoglutarate as the substrate, there followed regularly a sharp reduction, and eventually complete cessation, of oxygen consumption. This phenomenon was not observed when succinate was the substrate in the flasks, the finding pointing to a selective interference with DPN as the underlying change. The agent in the solutions of streptolysin O responsible for this effect was shown to be a streptococcal product, and to be non-dialyzable and heat-labile. It differed from streptolysin O in that it did not appear to require prior activation with cysteine, and its effectiveness was not diminished by treatment with cholesterol or antistreptolysin globulins.

Myocardial anaerobic metabolism in intact dogs

1963 ◽  
Vol 204 (3) ◽  
pp. 427-432 ◽  
Author(s):  
William A. Neill ◽  
Norman Krasnow ◽  
Herbert J. Levine ◽  
Richard Gorlin
Keyword(s):  
Energy Source ◽  
Oxygen Consumption ◽  
Oxidative Metabolism ◽  
Anaerobic Metabolism ◽  
Muscle Metabolism ◽  
Mechanical Work ◽  
Work Output ◽  
Heart Work ◽  
Anaerobic Energy ◽  
The Difference

Energy liberated from substrates of heart muscle metabolism appears as mechanical work and heat. External mechanical work and heat production of the left ventricle were compared with its oxygen consumption in intact dogs. Under control conditions, within the range of accuracy possible, the sum of work and heat was equal to energy from oxidative metabolism. Intravascular administration of cyanide increased heart work but reduced its rate of aerobic metabolism. During the cyanide effect, work plus heat exceeded the energy available from oxidative metabolism. The difference represents myocardial anaerobic metabolism. Since the energy of mechanical work output alone was greater than the myocardial aerobic energy source, a portion of the anaerobic energy liberated must have been converted to mechanical work.

Adrenal hormones and oxidative metabolism of the garden lizard (Calotes versicolor)

1983 ◽  
Vol 99 (2) ◽  
pp. 211-216 ◽  
Author(s):  
B. B. Pd. Gupta ◽  
J. P. Thapliyal
Keyword(s):  
Oxygen Consumption ◽  
Thyroid Hormones ◽  
Oxidative Metabolism ◽  
Whole Body ◽  
Endocrine Glands ◽  
Adrenal Hormones ◽  
Calotes Versicolor ◽  
Specific Tissue ◽  
Almost All ◽  
Stimulation Of

Daily administration of adrenaline over a 10-day period invariably induced significant increases in the metabolic rate of the whole body and of specific tissue (liver, muscle, kidney and brain) of both intact and thyroidectomized lizards except during June (breeding season) when the presence of thyroid hormones was a prerequisite for the stimulation of oxygen consumption by the whole body, muscle, kidney and brain but not by the liver. Corticosterone had no effect on whole body oxygen consumption but stimulated, inhibited or was without influence on the oxygen consumption of individual tissues, depending on the season and the presence or absence of thyroid hormones. It is suggested that adrenaline, due to its temperature-independent calorigenic effect, acts as the emergency hormone for energy release and helps the animal to survive during hibernation (winter months) when almost all the endocrine glands are inactive.

scholarly journals Coupling among growth rate response, metabolic cycle, and cell division cycle in yeast

2011 ◽  
Vol 22 (12) ◽  
pp. 1997-2009 ◽  
Author(s):  
Nikolai Slavov ◽  
David Botstein
Keyword(s):  
Growth Rate ◽  
Oxygen Consumption ◽  
Cell Division ◽  
Carbon Source ◽  
Oxidative Metabolism ◽  
Sole Source ◽  
Cell Division Cycle ◽  
Steady State Responses ◽  
Yeast Metabolic Cycle ◽  
Metabolic Cycle

We studied the steady-state responses to changes in growth rate of yeast when ethanol is the sole source of carbon and energy. Analysis of these data, together with data from studies where glucose was the carbon source, allowed us to distinguish a “universal” growth rate response (GRR) common to all media studied from a GRR specific to the carbon source. Genes with positive universal GRR include ribosomal, translation, and mitochondrial genes, and those with negative GRR include autophagy, vacuolar, and stress response genes. The carbon source–specific GRR genes control mitochondrial function, peroxisomes, and synthesis of vitamins and cofactors, suggesting this response may reflect the intensity of oxidative metabolism. All genes with universal GRR, which comprise 25% of the genome, are expressed periodically in the yeast metabolic cycle (YMC). We propose that the universal GRR may be accounted for by changes in the relative durations of the YMC phases. This idea is supported by oxygen consumption data from metabolically synchronized cultures with doubling times ranging from 5 to 14 h. We found that the high oxygen consumption phase of the YMC can coincide exactly with the S phase of the cell division cycle, suggesting that oxidative metabolism and DNA replication are not incompatible.

Influence of fasting on lung oxygen consumption and respiratory quotient

1976 ◽  
Vol 230 (2) ◽  
pp. 291-294 ◽  
Author(s):  
CA Gregorio ◽  
DB Gail ◽  
D Massaro
Keyword(s):  
Oxygen Consumption ◽  
Food Deprivation ◽  
Oxidative Metabolism ◽  
Respiratory Quotient ◽  
Reaction Medium ◽  
Oxidative Processes ◽  
Oxidation Of Glucose ◽  
Fasted Rats

We measured the oxygen consumption (QO2) of lung slices from rats and rabbits and the respiratory quotient (RQ) of lung slices from fed and fasted rats. The QO2 of lung slices is lowered within 24 h after the onset of food deprivation; this decrease in QO2 lasts during at least 2 additional days of fasting and is not eliminated by addition of glucose to the reaction medium. In fed rats the RQ of lung slices after 30 min of incubation without glucose is 0.75 +/- 0.01 (mean +/- SE) and 0.96 +/- 0.02 with glucose present. Fasting for 72 h lowers the RQ of lung slices after 30 min of incubation without glucose to 0.68 +/- 0.03; addition of glucose raises the RQ of lung slices from 72-h-fasted rats to 0.76 +/- 0.02. We conclude that fasting depresses lung oxidative metabolism. In the fed rat glucose is a major substrate for oxidative processes but in the fasting rat the oxidation of glucose is impaired and lipids are an important source of lung energy.

scholarly journals Mechanochemical Coupling in Flagella

1968 ◽  
Vol 52 (2) ◽  
pp. 283-299 ◽  
Author(s):  
C. J. Brokaw ◽  
B. Benedict
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Metabolism ◽  
Acid Production ◽  
Energy Requirement ◽  
Beat Frequency ◽  
Radius Of Curvature ◽  
Mechanochemical Coupling ◽  
Tightly Coupled ◽  
Dilute Suspensions ◽  
Stoichiometric Relation

The relation between oxygen consumption and motility of Ciona spermatozoa has been measured by using pH stats to measure the acid production of spermatozoa swimming in dilute suspensions where their motility can be analyzed accurately, and calibrating the acid production by measuring it simultaneously with measurements of oxygen consumption, using more concentrated sperm suspensions. When the motility of the spermatozoa is inhibited by thiourea or by increased viscosity, their oxygen consumption decreases in proportion to the decrease in beat frequency. 80–85 % of their oxygen consumption appears to be tightly coupled to motility. The amount of movement-coupled oxidative metabolism per beat remains nearly constant, even when there are significant changes in the energy required per beat for movement against the viscous resistance of the medium. This implies that under these conditions, where the radius of curvature of flagellar bending remains constant, the amount of ATP used is determined by a stoichiometric relation to bending rather than by the energy requirement. The movement-coupled oxidative metabolism appears to be sufficient to generate approximately two molecules of ATP per beat for each molecule of the flagellar ATPase, dynein.

Increased oxidative metabolism in renal tubules from spontaneously hypertensive rats

1989 ◽  
Vol 257 (5) ◽  
pp. F818-F825 ◽  
Author(s):  
P. C. Brazy ◽  
P. E. Klotman
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Metabolism ◽  
Spontaneously Hypertensive Rats ◽  
Antihypertensive Agents ◽  
Systemic Hypertension ◽  
Renal Tubules ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Consumption Rates ◽  
Relationship Of

Genetic hypertension in the rat is associated with abnormal renal function. This may be due to systemic hypertension or to intrinsic alterations in the kidney. Therefore, we examined intrinsic rates of oxidative metabolism in renal cortical tubules isolated from spontaneously hypertensive rats (SHR) and age-matched normotensive controls (WKY) before, during, and after the development of hypertension. We examined tubule function in SHR and WKY treated with antihypertensive agents to block the development of hypertension. During the early phase of hypertension (ages 7-8 wk), SHR tubules have intrinsic rates of oxygen consumption that are 15-25% greater than that of WKY. Ouabain-sensitive rates of oxygen consumption, an index of sodium entry, and Na+-K+-ATPase activity were not increased by 17%. Reduction of blood pressure with drugs did not abolish these differences in oxidative metabolism. Addition of exogenous arachidonic acid (1 microM) did reduce the metabolic differences between 8-wk-old SHR and WKY tubules. Norepinephrine (1 microM) had a greater stimulatory effect on oxygen consumption rates in tubules from hypertensive SHR. The relationship of these metabolic differences to the development of hypertension remains unclear.

The Use of Alpha-Methyl-p-Tyrosine to Control Circulating Catecholamtnes in The Dogfish Scyliorhinus Canicula: The Effects on Gas Exchange in Normoxia and Hypoxia

1989 ◽  
Vol 141 (1) ◽  
pp. 21-32 ◽  
Author(s):  
J. D. METCALFE ◽  
P. J. BUTLER
Keyword(s):  
Oxygen Consumption ◽  
Gas Exchange ◽  
Cardiovascular System ◽  
Direct Effect ◽  
Oxidative Metabolism ◽  
Oxygen Delivery ◽  
Cellular Level ◽  
Catecholamine Synthesis ◽  
Scyliorhinus Canicula ◽  
Circulating Levels

We assessed the effectiveness of alpha-methyl-p-tyrosine in inhibiting catecholamine synthesis in the dogfish and examined the effects of catecholamine depletion on the cardiovascular system in normoxia and in response to hypoxia. Although alpha-methyl-p-tyrosine (50mgday−1 intraperitoneally for 5 days) substantially reduced the dogfish's ability to increase the level of circulating catecholamines in response to hypoxia, it also substantially reduced normoxic oxygen consumption in the whole animal, an observation not previously reported. Metabolic studies on isolated dogfish hepatocytes indicate that this is a direct effect on oxidative metabolism at the cellular level rather than any effect on the oxygen delivery function of the fish's cardiovascular system. Despite the effects of alpha-methyl tyrosine on normoxic oxygen consumption, the present results indicate that the lack of any large increase in the circulating levels of catecholamines in response to hypoxia in fish treated with alpha-methyl tyrosine does not compromise their gas exchange ability.

scholarly journals Glycolysis in Neurons, Not Astrocytes, Delays Oxidative Metabolism of Human Visual Cortex during Sustained Checkerboard Stimulation in vivo

2001 ◽  
Vol 21 (12) ◽  
pp. 1384-1392 ◽  
Author(s):  
Albert Gjedde ◽  
Sean Marrett
Keyword(s):  
Oxygen Consumption ◽  
Visual Cortex ◽  
Glucose Metabolism ◽  
Oxidative Metabolism ◽  
Time Course ◽  
Complex Stimulus ◽  
Neuronal Activation ◽  
Positron Emission ◽  
Stimulation Of

The regulation of brain energy metabolism during neuronal activation is poorly understood. Specifically, the extent to which oxidative metabolism rather than glycolysis supplies the additional ATP necessary to sustain neuronal activation is in doubt. A recent hypothesis claims that astrocytes generate lactate with the muscle-type lactate dehydrogenase (LDH) isozyme LD5. Lactate from astrocytes then undergoes oxidation in neurons after reconversion to pyruvate by the LDH subtype LD1. On the basis of this hypothesis, the authors predicted that the time course of an excitatory increase of the oxidative metabolism of brain tissue must depend on the degree to which astrocytes provide neurons with pyruvate in the form of lactate. From the known properties of the LDH subtypes, the authors predicted two time courses for the changes of oxygen consumption in response to neuronal stimulation: one reflecting the properties of the neuronal LDH subtype LD1, and the other reflecting the astrocytic LDH subtype LD5. Measuring oxygen consumption (CMR o2) with positron emission tomography, the authors demonstrated increased CMR o2 during sustained stimulation of visual cortex with a complex stimulus. The CMR o2 increased 20.5% after 3 minutes and 27.5% after 8 minutes of stimulation, consistent with a steady-state oxygen–glucose metabolism ratio of 5.3, which is closest to the index predicted for the LD1 subtype. The index is equal to the oxygen–glucose metabolism ratio of 5.5 calculated at baseline, indicating that pyruvate is converted to lactate in a cellular compartment with an LDH reaction closest to that of LD1, whether at rest or during stimulation of the visual cortex with the current stimulus. The findings are consistent with a claim that neurons increase their oxidative metabolism in parallel with an increase of pyruvate, the latter generated by neuronal rather than astrocytic glycolysis.

Continuous recording of C14O2 excretion and O2 consumption by rats

1965 ◽  
Vol 20 (3) ◽  
pp. 558-560 ◽  
Author(s):  
M. W. Simpson-Morgan
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Metabolism ◽  
Respiratory Quotient ◽  
Continuous Recording ◽  
Laboratory Animals ◽  
O2 Consumption ◽  
Labeled Compounds ◽  
Small Laboratory

An apparatus is described with which the O2 consumption and C14O2 excretion of small laboratory animals can be recorded and integrated continuously during the course of experiments with C14-labeled compounds. In addition, the total CO2 production throughout intervals can be determined and the respiratory quotient calculated. The oxygen consumption apparatus is simple, inexpensive, and sensitive, and can be used in any closed metabolism system. apparatus; isotope; oxidative metabolism Submitted on July 10, 1964

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