title: Intracellular pro-oxidant activity of melatonin deprives U937 cells of reduced glutathione without affecting glutathione peroxidase activity.
abstract: It was long believed that melatonin might counteract intracellular oxidative stress because it was shown to potentiate antioxidant endogenous defences, and to increase the activity of many antioxidant enzymes. However, it is now becoming evident that when radicals are measured within cells, melatonin increases, rather than decreasing, radical production. Herein we demonstrate a pro-oxidant effect of melatonin in U937 cells by showing an increase of intracellular oxidative species and a depletion of glutathione (GSH). The activity of glutathione peroxidase is not modified by melatonin treatment as it does occur in other experimental models.
authors.affiliation: Istituto di Chimica Biologica G. Fornaini, Via Saffi 2, 61029 Urbino, Italy. cemetbio@uniurb.it
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Albertini
authors.forename: Flavia
authors.initials: F
authors.lastname: Radogna
authors.forename: Augusto
authors.initials: A
authors.lastname: Accorsi
authors.forename: Francesco
authors.initials: F
authors.lastname: Uguccioni
authors.forename: Laura
authors.initials: L
authors.lastname: Paternoster
authors.forename: Claudia
authors.initials: C
authors.lastname: Cerella
authors.forename: Milena
authors.initials: M
authors.lastname: De Nicola
authors.forename: Maria
authors.initials: M
authors.lastname: D'Alessio
authors.forename: Antonio
authors.initials: A
authors.lastname: Bergamaschi
authors.forename: Andrea
authors.initials: A
authors.lastname: Magrini
authors.forename: Lina
authors.initials: L
authors.lastname: Ghibelli
mesh_terms: D004789:Enzyme Activation / Q000502:physiology; D005978:Glutathione / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D007424:Intracellular Fluid / Q000201:enzymology / Q000378:metabolism*; D008550:Melatonin / Q000502:physiology*; D016877:Oxidants / Q000502:physiology*; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism; D020298:U937 Cells
chemical_list: D016877:Oxidants; D017382:Reactive Oxygen Species; D005979:Glutathione Peroxidase; D005978:Glutathione; D008550:Melatonin