title: Endogenous rhythms of melatonin, total antioxidant status and superoxide dismutase activity in several tissues of chick and their inhibition by light.
abstract: Melatonin was recently shown to be a component of the antioxidative defense system of organisms due to its free radical scavenging ability and to its capacity to stimulate several antioxidant enzymes. In this report, we studied the endogenous rhythm of the antioxidant enzyme superoxide dismutase (SOD) in three different tissues (cerebral cortex, liver and lung) of chick (Gallus domesticus) (three weeks, at age and sacrificed every 2 hr). During the study the chicks were under a light:dark cycle of 12:12. Total antioxidant status of the plasma was correlated with physiological blood melatonin concentrations. Superoxide dismutase activity exhibited a marked 24 hr rhythm in cerebral cortex, lung and liver, with peak activity coincident with the melatonin and total antioxidant status peaks. The exposure of chicks to constant light for 7 days eliminated the melatonin rhythm as well as the peaks in superoxide dismutase activity and the total antioxidant status. These findings suggest that the melatonin rhythm may be related to the nighttime increase in the superoxide dismutase activity and to total antioxidant capacity of the blood.
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, The University of Valladolid, Spain.
authors.forename: M T
authors.initials: MT
authors.lastname: Albarrán
authors.forename: S
authors.initials: S
authors.lastname: López-Burillo
authors.forename: M I
authors.initials: MI
authors.lastname: Pablos
authors.forename: R J
authors.initials: RJ
authors.lastname: Reiter
authors.forename: M T
authors.initials: MT
authors.lastname: Agapito
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D002645:Chickens / Q000097:blood / Q000378:metabolism*; D008027:Light; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D008550:Melatonin / Q000097:blood / Q000378:metabolism*; D010507:Periodicity; D017440:Photoperiod; D013482:Superoxide Dismutase / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D000975:Antioxidants; D013482:Superoxide Dismutase; D008550:Melatonin