Exercise training increases creatine kinase capacity in canine myocardium

Area of Science:

• Cardiovascular Physiology
• Exercise Science
• Biochemistry

Background:

• The creatine kinase (CK) system is crucial for energy transport in cardiomyocytes.
• While its response to hemodynamic overload is known, effects of aerobic exercise are less clear.

Purpose of the Study:

• To investigate the impact of aerobic exercise training on the myocardial CK system in dogs.
• To test if exercise training increases the capacity of the CK system in canine myocardium.

Main Methods:

• Dogs underwent a 9-week treadmill running program or were cage-rested.
• Total CK activity was measured colorimetrically.
• CK-MB isoenzyme activity was determined via electrophoresis.

Main Results:

• Aerobic training increased left ventricular total CK activity by 46%.
• Left ventricular CK-MB isoenzyme activity increased 4.5-fold and its fraction of total CK threefold.
• Right ventricular CK activity and CK-MB levels remained unchanged.

Conclusions:

• Aerobic exercise enhances total CK activity and CK-MB content in the left ventricle of canine hearts.
• The right ventricle's CK system showed no significant changes post-training.
• CK-MB remains a minor but increased component of the left ventricular CK system after training.