| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1AstraZeneca R&D, Mölndal, Sweden; 2University of Tromsø, Tromsø, Norway; 3Garvan Institute, Sydney, Australia; and 4University of Calgary, Calgary, Alberta, Canada
Submitted 25 May 2005 ; accepted in final form 6 December 2005
Studies of cardiac fuel metabolism in mice have been almost exclusively conducted ex vivo. The major aim of this study was to assess in vivo plasma FFA and glucose utilization by the hearts of healthy control (db/+) and diabetic (db/db) mice, based on cardiac uptake of (R)-2-[9,10-3H]bromopalmitate ([3H]R-BrP) and 2-deoxy-D-[U-14C]glucose tracers. To obtain quantitative information about the evaluation of cardiac FFA utilization with [3H]R-BrP, simultaneous comparisons of [3H]R-BrP and [14C]palmitate ([14C]P) uptake were first made in isolated perfused working hearts from db/+ mice. It was found that [3H]R-BrP uptake was closely correlated with [14C]P oxidation (r2 = 0.94, P < 0.001). Then, methods for in vivo application of [3H]R-BrP and [14C]2-DG previously developed for application in the rat were specially adapted for use in the mouse. The method yields indexes of cardiac FFA utilization (Rf*) and clearance (Kf*), as well as glucose utilization (Rg'). Finally, in the main part of the study, the ability of the heart to switch between FFA and glucose fuels (metabolic flexibility) was investigated by studying anesthetized, 8-h-fasted control and db/db mice in either the basal state or during glucose infusion. In control mice, glucose infusion raised plasma levels of glucose and insulin, raised Rg' (+58%), and lowered plasma FFA level (–48%), Kf* (–45%), and Rf* (–70%). This apparent reciprocal regulation of glucose and FFA utilization by control hearts illustrates metabolic flexibility for substrate use. By contrast, in the db/db mice, glucose infusion raised glucose levels with no apparent influence on cardiac FFA or glucose utilization. In conclusion, tracer methodology for assessing in vivo tissue-specific plasma FFA and glucose utilization has been adapted for use in mice and reveals a profound loss of metabolic flexibility in the diabetic db/db heart, suggesting a fixed level of FFA oxidation in fasted and glucose-infused states.
fatty acid; glucose; metabolic flexibility; bromopalmitate tracer; deoxyglucose tracer
This article has been cited by other articles:
|
|
 |
|
  J. Shearer, D. L. Severson, L. Su, L. Belardinelli, and A. K. Dhalla Partial A1 Adenosine Receptor Agonist Regulates Cardiac Substrate Utilization in Insulin-Resistant Rats in Vivo J. Pharmacol. Exp. Ther., January 1, 2009; 328(1): 306 - 311. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Boudina, S. Sena, H. Theobald, X. Sheng, J. J. Wright, X. X. Hu, S. Aziz, J. I. Johnson, H. Bugger, V. G. Zaha, et al. Mitochondrial Energetics in the Heart in Obesity-Related Diabetes: Direct Evidence for Increased Uncoupled Respiration and Activation of Uncoupling Proteins Diabetes, October 1, 2007; 56(10): 2457 - 2466. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Boudina and E. D. Abel Diabetic Cardiomyopathy Revisited Circulation, June 26, 2007; 115(25): 3213 - 3223. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Yue, T. Arai, M. Terashima, A. Y. Sheikh, F. Cao, D. Charo, G. Hoyt, R. C. Robbins, E. A. Ashley, J. Wu, et al. Magnetic resonance imaging of progressive cardiomyopathic changes in the db/db mouse Am J Physiol Heart Circ Physiol, May 1, 2007; 292(5): H2106 - H2118. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
