TY - JOUR
T1 - Rhythms of glutathione peroxidase and glutathione reductase in brain of chick and their inhibition by light
AU - Pablos, Marta I.
AU - Reiter, Russel J.
AU - Ortiz, Genaro G.
AU - Guerrero, Juan M.
AU - Agapito, Maria T.
AU - Chuang, Jin Ing
AU - Sewerynek, Ewa
N1 - Funding Information:
Acknowledgements--MIP is supported by a NATO grant. MTA is supported by a grant of University of Valladolid and Junta de Castilla y Leon. Research was supported by grants from NIH and NSF.
PY - 1998/1
Y1 - 1998/1
N2 - Melatonin was recently shown to be a component of the antioxidative defense system of organisms due to its free radical scavenging and antioxidant activities. Pharmacologically, melatonin stimulates the activity of the peroxide detoxifying enzyme glutathione peroxidase in rat brain and in several tissues of chicks. In this report, we studied the endogenous rhythm of two antioxidant enzymes, glutathione peroxidase and glutathione reductase, in five regions (hippocampus, hypothalamus, striatum, cortex and cerebellum) of chick brain and correlated them with physiological blood melatonin concentrations. Glutathione peroxidase exhibited a marked 24 h rhythm with peak activity in each brain region which had acrophases about 8 h after lights off and about 4 h after the serum melatonin peak was detected. Glutathione reductase activity exhibited similar robust rhythms with the peaks occurring roughly 2 h after those of glutathione peroxidase. We suggest that neural glutathione peroxidase increases due to the rise of nocturnal melatonin levels while glutathione reductase activity rises slightly later possibly due to an increase of its substrate, oxidized glutathione. The exposure of chicks to constant light for 6 days eliminated the melatonin rhythm as well as the peaks in both glutathione peroxidase and glutathione reductase activities. These findings suggest that the melatonin rhythm may be related to the night time increases in the enzyme activities, although other explanations cannot be excluded.
AB - Melatonin was recently shown to be a component of the antioxidative defense system of organisms due to its free radical scavenging and antioxidant activities. Pharmacologically, melatonin stimulates the activity of the peroxide detoxifying enzyme glutathione peroxidase in rat brain and in several tissues of chicks. In this report, we studied the endogenous rhythm of two antioxidant enzymes, glutathione peroxidase and glutathione reductase, in five regions (hippocampus, hypothalamus, striatum, cortex and cerebellum) of chick brain and correlated them with physiological blood melatonin concentrations. Glutathione peroxidase exhibited a marked 24 h rhythm with peak activity in each brain region which had acrophases about 8 h after lights off and about 4 h after the serum melatonin peak was detected. Glutathione reductase activity exhibited similar robust rhythms with the peaks occurring roughly 2 h after those of glutathione peroxidase. We suggest that neural glutathione peroxidase increases due to the rise of nocturnal melatonin levels while glutathione reductase activity rises slightly later possibly due to an increase of its substrate, oxidized glutathione. The exposure of chicks to constant light for 6 days eliminated the melatonin rhythm as well as the peaks in both glutathione peroxidase and glutathione reductase activities. These findings suggest that the melatonin rhythm may be related to the night time increases in the enzyme activities, although other explanations cannot be excluded.
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U2 - 10.1016/S0197-0186(97)00043-0
DO - 10.1016/S0197-0186(97)00043-0
M3 - Article
C2 - 9460704
AN - SCOPUS:0031975809
SN - 0197-0186
VL - 32
SP - 69
EP - 75
JO - Neurochemistry International
JF - Neurochemistry International
IS - 1
ER -