Intracellular pro-oxidant activity of melatonin deprives U937 cells of reduced glutathione without affecting glutathione peroxidase activity.
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.
Albertini
Maria Cristina
MC
Istituto di Chimica Biologica G. Fornaini, Via Saffi 2, 61029 Urbino, Italy. cemetbio@uniurb.it
Radogna
Flavia
F
Accorsi
Augusto
A
Uguccioni
Francesco
F
Paternoster
Laura
L
Cerella
Claudia
C
De Nicola
Milena
M
D'Alessio
Maria
M
Bergamaschi
Antonio
A
Magrini
Andrea
A
Ghibelli
Lina
L
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
D016877:Oxidants; D017382:Reactive Oxygen Species; D005979:Glutathione Peroxidase; D005978:Glutathione; D008550:Melatonin