Calcium regulation of glycolysis, glucose oxidation, and fatty acid oxidation in the aerobic and ischemic heart

Can J Physiol Pharmacol. 1995 Nov;73(11):1632-40. doi: 10.1139/y95-725.


Although Ca2+ is an important regulator of energy metabolism, the effects of increasing extracellular [Ca2+] on energy substrate preference are not clear. We determined the relationship between [Ca2+], fatty acids, and ischemia on rates of glycolysis, glucose oxidation, and palmitate oxidation in isolated working rat hearts. Hearts were perfused with Krebs-Henseleit buffer containing 11 mM glucose, 100 microU/mL insulin, and either 1.25 or 2.5 mM Ca2+, in the presence or absence of 1.2 mM palmitate. Rates of glycolysis and glucose oxidation or palmitate oxidation were measured in the hearts using [5-3H,14C(U)]glucose or [1-14C]palmitate, respectively. In the absence of fatty acids, glycolysis and glucose oxidation rates were similar, regardless of whether [Ca2+ was 1.25 or 2.5 mM. Addition of 1.2 mM palmitate to the perfusate of hearts perfused with 1.25 mM Ca2+ significantly decreased rates of both glycolysis (from 4623 +/- 438 to 1378 +/- 238 nmol.min-1.g-1 dry weight) and glucose oxidation (from 1392 +/- 219 to 114 +/- 22 nmol.min-1.g-1 dry weight). When [Ca2+] was increased from 1.25 to 2.5 mM in hearts perfused with 1.2 mM palmitate, glycolysis and glucose oxidation increased by 164 and 271%, respectively, with no change in palmitate oxidation rates. Increasing [Ca2+] from 1.25 to 2.5 mM increased the contribution of glucose to ATP production from 9.3 to 18.7%. When hearts were subjected to low-flow ischemia (by reducing coronary flow to 0.5 mL.min-1) oxidative metabolism was essentially abolished. Under these conditions, glycolytic rates were not dependent on either [Ca2+] or the presence or absence of fatty acids. These results demonstrate that perfusate [Ca2+] is an important determinant of myocardial glucose metabolism in aerobic hearts, and that glycolysis and glucose oxidation are more responsive to changes in [Ca2+] than is fatty acid oxidation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / biosynthesis
  • Aerobiosis
  • Animals
  • Calcium / physiology*
  • Fatty Acids / metabolism*
  • Glucose / metabolism*
  • Glycogen / metabolism
  • Glycolysis / physiology*
  • In Vitro Techniques
  • Male
  • Myocardial Contraction / drug effects
  • Myocardial Ischemia / metabolism*
  • Myocardium / metabolism*
  • Oxidation-Reduction
  • Palmitic Acids / metabolism
  • Perfusion
  • Rats
  • Rats, Sprague-Dawley


  • Fatty Acids
  • Palmitic Acids
  • Adenosine Triphosphate
  • Glycogen
  • Glucose
  • Calcium