TY - JOUR
T1 - Exercise training enhances glycolytic and oxidative enzymes in canine ventricular myocardium
AU - Stuewe, Steven R.
AU - Gwirtz, Patricia A.
AU - Agarwal, Neeraj
AU - Mallet, Robert T.
N1 - Funding Information:
This work was supported by funding from the National Heart, Lung and Blood Institute to RTM (HL 50441) and PAG (HL 34172), and by an American College of Sports Medicine Foundation grant to SRS. SRS is the recipient of a predoctoral fellowship from the Graduate School of Biomedical Sciences of the University of North Texas Health Science Center at Fort Worth. This investigation was completed in partial fulfillment of the requirements for the Doctor of Philosophy degree for SRS at the University of North Texas Health Science Center. The assistance of Ms Linda Howard and Ms Traci Phelps in conducting the treadmill running program, and the technical support of Ms Jie Sun for electrophoresis and immunoblots is gratefully acknowledged. We are indebted to Drs Claudia Evans at the University of Texas Southwestern Medical Center, Dallas, TX, and Richard Gross at Washington University School of Medicine, St Louis, MO, for generously providing CS and GAPDH antibodies, respectively. We also thank Dr Kenneth Baldwin at the University of California, Irvine, CA, for his helpful insights and suggestions.
PY - 2000
Y1 - 2000
N2 - Aerobic exercise training evokes adaptations in the myocardial contractile machinery that enhance cardiac functional capacity: in comparison, the effects of training on the myocardium's energy generating pathways are less well characterized. This study tested the hypothesis that aerobic exercise training can increase the capacities of the major pathways of intermediary metabolism in canine myocardium. Mongrel dogs were conditioned by a 9-week treadmill running program or cage rested for 4 weeks. Exercise conditioning was evidenced by 26% and 22% decreases (P<O.05) in respective heart rates at rest and during submaximal exercise and by a 40% increase (P<O.05) in citrate synthase (CS) activity of the vastus lateralis. Glycolytic, TCA cycle, and β-oxidative enzymes were assayed in myocardial extracts at 37°C. Relative to sedentary controls, training increased glyceraldehyde 3-phosphate dehydrogenase (GAPDH) activity by 49% in left and 33% in right ventricle, and pyruvate kinase. CS, and 3-hydroxyacyl CoA dehydrogenase (HADH) activities by 74%. 91%. and 77%, respectively, in left ventricle (P<O.05). Immunoblotting further confirmed that training increased left ventricular contents of CS and GAPDH. Other measured enzymes (hexokinase, phosphofructokinase, lactate dehydrogenase, α-ketoglutarate dehydrogenase, malate dehydrogenase) were not altered by training in either ventricle. Kinetic analyses revealed increased maximum rates but unaltered substrate affinities of GAPDH, CS and HADH following training. Thus, aerobic exercise training augments the intermediary metabolic capacity of canine myocardium by selectively increasing the concentrations of regulatory enzymes of glycolysis and oxidative metabolism. (C) 2000 Academic Press.
AB - Aerobic exercise training evokes adaptations in the myocardial contractile machinery that enhance cardiac functional capacity: in comparison, the effects of training on the myocardium's energy generating pathways are less well characterized. This study tested the hypothesis that aerobic exercise training can increase the capacities of the major pathways of intermediary metabolism in canine myocardium. Mongrel dogs were conditioned by a 9-week treadmill running program or cage rested for 4 weeks. Exercise conditioning was evidenced by 26% and 22% decreases (P<O.05) in respective heart rates at rest and during submaximal exercise and by a 40% increase (P<O.05) in citrate synthase (CS) activity of the vastus lateralis. Glycolytic, TCA cycle, and β-oxidative enzymes were assayed in myocardial extracts at 37°C. Relative to sedentary controls, training increased glyceraldehyde 3-phosphate dehydrogenase (GAPDH) activity by 49% in left and 33% in right ventricle, and pyruvate kinase. CS, and 3-hydroxyacyl CoA dehydrogenase (HADH) activities by 74%. 91%. and 77%, respectively, in left ventricle (P<O.05). Immunoblotting further confirmed that training increased left ventricular contents of CS and GAPDH. Other measured enzymes (hexokinase, phosphofructokinase, lactate dehydrogenase, α-ketoglutarate dehydrogenase, malate dehydrogenase) were not altered by training in either ventricle. Kinetic analyses revealed increased maximum rates but unaltered substrate affinities of GAPDH, CS and HADH following training. Thus, aerobic exercise training augments the intermediary metabolic capacity of canine myocardium by selectively increasing the concentrations of regulatory enzymes of glycolysis and oxidative metabolism. (C) 2000 Academic Press.
KW - Glycolysis
KW - Immunoblotting
KW - Michaelis-Menten kinetics
KW - TCA cycle
KW - β-Oxidation
UR - http://www.scopus.com/inward/record.url?scp=0033841054&partnerID=8YFLogxK
U2 - 10.1006/jmcc.2000.1131
DO - 10.1006/jmcc.2000.1131
M3 - Article
C2 - 10888245
AN - SCOPUS:0033841054
SN - 0022-2828
VL - 32
SP - 903
EP - 913
JO - Journal of Molecular and Cellular Cardiology
JF - Journal of Molecular and Cellular Cardiology
IS - 6
ER -