Circadian variations in antioxidant defences and lipid peroxidation in the rat heart.
Free Radic Res Commun
; 17(3): 187-94, 1992.
Article
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| MEDLINE
| ID: mdl-1459491
ABSTRACT
Circadian variations in antioxidant defences and lipid peroxidation were investigated in 12 rat hearts perfused during light (i.e., at 08.00, n = 6) and dark cycle (i.e., at 19.00, n = 6). Higher levels of non proteic thiol compounds (P < 0.01), glutathione transferase activity (P < 0.05) and lipid peroxidation (P < 0.01) were detected in evening-excised hearts, associated with a lower (P < 0.05) selenium-dependent glutathione peroxidase activity; superoxide dismutase and glutathione reductase activities, as well as vitamin E content, were similar in the two groups. Moreover, a greater release of thiobarbituric acid reactive substances (P < 0.01) and proteins (P < 0.05) was detected in the myocardial effluent of another group of 5 evening-excised hearts perfused with Krebs-Henseleit buffer containing 30 microM cumene hydroperoxide, as compared to 5 light-cycle hearts. In conclusion, a higher oxidative stress seems to be operative in the rat heart during early stages of the dark phase, in spite of the increase level of non proteic thiol compounds (namely, glutathione). An imbalance of antioxidant defences, and/or higher radical generation and unsaturation degree of biomembranes lipids, may be hypothesized to favour myocardial oxidative stress at the beginning of the motor activity phase in rats.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Derivados del Benceno
/
Peroxidación de Lípido
/
Ritmo Circadiano
/
Miocardio
Límite:
Animals
Idioma:
En
Revista:
Free Radic Res Commun
Asunto de la revista:
QUIMICA
Año:
1992
Tipo del documento:
Article
País de afiliación:
Italia