N.m.r. studies of metabolism in perfused organs

1980 ◽  
Vol 289 (1037) ◽  
pp. 425-436 ◽  
Keyword(s):  
Heart Rate ◽  
Nuclear Magnetic Resonance ◽  
Rat Heart ◽  
Energy Supply ◽  
Saturation Transfer ◽  
Perfused Rat Heart ◽  
Perfusion Model ◽  
Metabolic Recovery ◽  
First Time

Several metabolites and intracellular pH in intact organs can be studied in a nondestructive manner by phosphorus nuclear magnetic resonance ( 31 P n.m.r.). This possibility was demonstrated by us nearly five years ago. Since then we have developed the appropriate physiological techniques and improved the n.m.r. method for the study of animal hearts and kidneys. Here we describe measurements aimed at clarifying three problems. (1) Having measured the enzyme-catalysed fluxes between phosphocreatine and ATP by the method of saturation transfer n.m.r., we examine the relation between energy supply and heart rate in the isolated perfused rat heart. (2) We describe experiments to establish the validity of the perfusion model. For the first time, we report 31 P n.m.r. measurements of an in vivo rat heart and compare the results with those obtained for the perfused rat heart. (3) Ischaemia and metabolism in rabbit kidneys is investigated to establish the relation between functional and metabolic recovery after a renal transplant operation.

Cardiac performance and creatine kinase flux during inhibition of ATP synthesis in the perfused rat heart

1999 ◽  
Vol 277 (1) ◽  
pp. H308-H317 ◽  
Author(s):  
P. Mateo ◽  
V. Stepanov ◽  
B. Gillet ◽  
J.-C. Beloeil ◽  
J. A. Hoerter
Keyword(s):  
Creatine Kinase ◽  
Rat Heart ◽  
Mechanical Performance ◽  
Diastolic Pressure ◽  
Atp Synthesis ◽  
Cardiac Performance ◽  
Rate Pressure Product ◽  
Saturation Transfer ◽  
Perfused Rat Heart ◽  
Performance Rate

To study the relation among mitochondrial energy supply, cardiac performance, and energy transfer through creatine kinase (CK), two acute models of inhibition of ATP synthesis were compared in the isovolumic acetate-perfused rat heart. Similar impairments of mechanical performance (rate-pressure product, RPP) were achieved by various stepwise decreases in O2 supply ([Formula: see text] down to 20% of control) or by infusing CN (0.15–0.25 mM). The forward CK flux measured by saturation-transfer 31P NMR spectroscopy was 6.1 ± 0.4 mM/s in control hearts. Only after severe hypoxia ([Formula: see text] < 40% of control) did CK flux drop (to 1.9 ± 0.2 mM/s at[Formula: see text] = 25% of control) together with impaired systolic activity and a rise in end-diastolic pressure. In contrast, in mild hypoxia CK flux remained constant and similar to control (5.3 ± 0.5 mM/s, not significant) despite a twofold reduction in systolic activity. Similarly in all CN groups, constant CK flux was maintained for a threefold reduction in RPP, showing the absence of a relation between cardiac performance and global NMR-measured CK flux during mild ATP synthesis inhibition.

scholarly journals The release of 3′:5′-cyclic monophosphate from the isolated perfused rat heart

1975 ◽  
Vol 152 (2) ◽  
pp. 429-432 ◽  
Author(s):  
John A. O'Brien ◽  
Richard C. Strange
Keyword(s):  
Cyclic Amp ◽  
Rat Heart ◽  
Perfused Rat Heart ◽  
Cyclic Monophosphate ◽  
Isolated Perfused Rat Heart ◽  
Rat Hearts ◽  
Basal Release ◽  
Perfused Rat Hearts ◽  
Isolated Perfused Rat Hearts

Although basal release of cyclic AMP from isolated perfused rat hearts was not measurable, isoprenaline induced substantial release of the nucleotide, suggesting that in vivo the myocardium can contribute to plasma cyclic AMP. Anoxia also increased the amount of cyclic AMP released, but insulin and nicotinate alone or in combination had no effect.

scholarly journals The effects of glucose, acetate, lactate and insulin on protein degradation in the perfused rat heart

1982 ◽  
Vol 206 (3) ◽  
pp. 467-472 ◽  
Author(s):  
P H Sugden ◽  
D M Smith
Keyword(s):  
Protein Degradation ◽  
Rat Heart ◽  
Plasma Concentrations ◽  
Normal Range ◽  
Perfused Rat Heart ◽  
Rat Hearts ◽  
Insulin Inhibition

Rat hearts were perfused as working preparations by the method of Taegtmeyer, Hems & Krebs [(1980 Biochem. J. 186, 701-711]. In the presence of glucose, insulin significantly inhibited protein degradation at concentrations as low as 50 mu units/ml. Acetate or lactate, when present either as sole fuel for contraction or in combination with glucose, did not inhibit protein degradation. Insulin inhibition or protein degradation was decreased with either lactate as sole fuel. We suggest that the inhibition of protein degradation occurs over the normal range of plasma concentrations of insulin present in vivo and that the presence of glucose may be at least in part necessary for this effect of insulin.

scholarly journals Analysis of rat heart in vivo by phosphorus nuclear magnetic resonance.

1980 ◽  
Vol 77 (1) ◽  
pp. 299-302 ◽  
Author(s):  
T. H. Grove ◽  
J. J. Ackerman ◽  
G. K. Radda ◽  
P. J. Bore
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Rat Heart ◽  
Nuclear Magnetic
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