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.

Energetics of the Frank-Starling effect in rabbit myocardium: economy and efficiency depend on muscle length

2002 ◽  
Vol 283 (1) ◽  
pp. H324-H330 ◽  
Author(s):  
Jeffrey W. Holmes ◽  
Mark Hünlich ◽  
Gerd Hasenfuss
Keyword(s):  
Oxygen Consumption ◽  
Muscle Length ◽  
Published Data ◽  
Average Force ◽  
Time Integral ◽  
Rabbit Myocardium ◽  
Efficiency Increase ◽  
Butanedione Monoxime ◽  
Force Time ◽  
Force Time Integral

We tested the hypothesis that economy and efficiency are independent of length in intact cardiac muscle over its normal working range. We measured force, force-time integral, force-length area, and myocardial oxygen consumption in eight isometrically contracting rabbit right ventricular papillary muscles. 2,3-Butanedione monoxime was used to partition nonbasal oxygen consumption into tension-independent and tension-dependent components. Developed force, force-time integral, and force-length area increased by factors of 2.4, 2.7, and 4.8, respectively, as muscle length was increased from 90% to 100% maximal length, whereas tension-dependent oxygen consumption increased only 1.6-fold. Economy (the ratio of force-time integral to tension-dependent oxygen consumption) increased significantly with muscle length, as did contractile efficiency, the ratio of force-length area to tension-dependent oxygen consumption. The average force-length area-nonbasal oxygen consumption intercept was more than the twice tension-independent oxygen consumption. We conclude that economy and efficiency increase with length in rabbit myocardium. This conclusion is consistent with published data in isolated rabbit and dog hearts but at odds with studies in skinned myocardium.

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.

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