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Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy
Published on: August 31, 2010
Elevated hexokinase increases cardiac glycolysis in transgenic mice
Qiangrong Liang1, Rajakumar V Donthi, Patricia M Kralik
1Department of Pharmacology, University of North Dakota, Grand Forks, ND 58202, USA.
Cardiovascular Research
|February 6, 2002
Summary
This study shows that increasing glucose phosphorylation in the heart boosts glucose metabolism during normal function but not during ischemia. This highlights glucose phosphorylation as a key step in cardiac energy production.
Area of Science:
- Cardiology
- Metabolic Research
- Molecular Biology
Background:
- Cardiac glucose metabolism is vital for heart function and disease.
- The role of the initial step, glucose phosphorylation, in cardiac glycolysis remains unclear.
Purpose of the Study:
- To investigate the significance of glucose phosphorylation in cardiac glycolysis using a novel transgenic model.
- To determine the impact of enhanced glucose phosphorylation on cardiac glucose metabolism and function.
Main Methods:
- Developed transgenic mice overexpressing yeast hexokinase B (a high-affinity enzyme) in the heart.
- Measured hexokinase activity, cardiac glucose metabolism, contractility, and glycogen content.
- Utilized Langendorff perfusion and radiometric assays for precise measurements.
Main Results:
- Transgenic hearts exhibited significantly elevated hexokinase activity and increased glucose metabolism, especially with insulin and during reperfusion.
- Glycolysis was minimally affected by the transgene during ischemic perfusion.
- Cardiac glycogen content doubled, and glucose-6-phosphate independent glycogen synthase activity increased, with no impact on contractility.
Conclusions:
- Glucose phosphorylation is a critical determinant of cardiac glucose metabolism under oxidative conditions.
- Targeting glucose phosphorylation may influence cardiac energy metabolism in specific physiological states.
