title: Exercise preconditioning against hydrogen peroxide-induced oxidative damage in proteins of rat myocardium.
abstract: Both regular physical exercise and low levels of H(2)O(2) administration result in increased resistance to oxidative stress. We measured the accumulation of reactive carbonyl derivatives and the activities of proteasome complex and DT-diaphorase in cardiac muscle of trained and untrained rats after chronic i.p. administration of 1 ml t-butyl H(2)O(2) (1 mmol/kg for 3 weeks every second day). Twenty-four rats were randomly assigned to a control group administered with saline, control administered with H(2)O(2), and exercised administered either saline or H(2)O(2). The activity of DT-diaphorase significantly increased in H(2)O(2) administered and exercised groups, indicating that an increase in H(2)O(2) levels stimulate the activity of this enzyme. The cardiac muscle of H(2)O(2) administered nonexercised animals accumulated significantly more carbonyl than control group (P < 0.05). The exercise and H(2)O(2) administration resulted in less oxidatively modified protein than found in nonexercised groups (P < 0.05). The peptide-like activity of proteasome complex was induced by the treatment of H(2)O(2) and exercise and exercise potentiate the effect of H(2)O(2). On the other hand, the chymotrypsin-like and trypsin-like activities were stimulated only by physical training and H(2)O(2) administration. The data suggest that chronic administration of H(2)O(2) after exercise training decreases the accumulation of carbonyl groups below the steady-state level and induces the activity of proteasome and DT-diaphorase. Hence, the stimulating effect of physical exercise on free radical generation is an important phenomenon of the exercise-induced adaptation process since it increases resistance to oxidative stress. Regular exercise training is a valuable physiological means of preconditioning the myocardium to prolonged oxidative stress.
authors.affiliation: Laboratory of Exercise Physiology, Semmelweis University, Budapest, Hungary.
authors.forename: Z
authors.initials: Z
authors.lastname: Radák
authors.forename: M
authors.initials: M
authors.lastname: Sasvári
authors.forename: C
authors.initials: C
authors.lastname: Nyakas
authors.forename: J
authors.initials: J
authors.lastname: Pucsok
authors.forename: H
authors.initials: H
authors.lastname: Nakamoto
authors.forename: S
authors.initials: S
authors.lastname: Goto
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002918:Chymotrypsin / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism*; D018384:Oxidative Stress; D010805:Physical Conditioning, Animal / Q000502:physiology*; D046988:Proteasome Endopeptidase Complex; D051381:Rats; D017208:Rats, Wistar; D013550:Swimming / Q000502:physiology; D014357:Trypsin / Q000378:metabolism
chemical_list: D000975:Antioxidants; D009097:Multienzyme Complexes; D006861:Hydrogen Peroxide; D008058:Dihydrolipoamide Dehydrogenase; D002950:Citrate (si)-Synthase; D002918:Chymotrypsin; D014357:Trypsin; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex