title: Does exercise training alter myocardial creatine kinase MB isoenzyme content?
abstract: Skeletal muscle biopsies from highly trained endurance athletes have been shown to contain an increased percentage of the creatine kinase MB (CK-MB) isoenzyme, which has been attributed to continuous regeneration of the skeletal muscle fibers in response to exercise-induced injury. The purpose of this study was to determine whether myocardium undergoes a similar degenerative-regenerative process as a result of exercise training. Fifteen mongrel dogs underwent a 12-wk period of training (N = 8) or cage confinement (N = 7). The animals were then sacrificed, and samples of left and right ventricular myocardium were analyzed for total CK activity and CK-MB isoenzyme content. Percentages of CK-MB were slightly but insignificantly higher from both ventricles of exercise-trained as compared with cage-confined dogs: left ventricle, 4.6 +/- 0.6% vs 3.3 +/- 0.6%, respectively (P = 0.15); right ventricle, 4.0 +/- 0.4% vs 3.0 +/- 0.8%, respectively (P = 0.29). We conclude that chronic exercise training does not induce physiologically important degenerative changes in myocardium.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, MN 55905.
authors.forename: T D
authors.initials: TD
authors.lastname: Miller
authors.forename: P J
authors.initials: PJ
authors.lastname: Rogers
authors.forename: B A
authors.initials: BA
authors.lastname: Bauer
authors.forename: J F
authors.initials: JF
authors.lastname: O'Brien
authors.forename: R W
authors.initials: RW
authors.lastname: Squires
authors.forename: K R
authors.initials: KR
authors.lastname: Bailey
authors.forename: A A
authors.initials: AA
authors.lastname: Bove
mesh_terms: D000818:Animals; D003402:Creatine Kinase / Q000378:metabolism*; D004285:Dogs; D007527:Isoenzymes; D009206:Myocardium / Q000201:enzymology*; D010805:Physical Conditioning, Animal
chemical_list: D007527:Isoenzymes; D003402:Creatine Kinase