Circadian Variation Of Antioxidant Enzymes And TBARs In Hippocampus Of Vitamin A deficient rats.

NAVIGATORE FONZO, L.S.; DELGADO, S. M.; BONOMI M.R.; REZZA, I. G.; GIMÉNEZ MS; ANZULOVICH A.C.

Mar del Plata, Bs. As.

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2007

SAIB

NS-P02.CIRCADIAN VARIATION OF ANTIOXIDANT ENZYMESAND TBARS IN HIPPOCAMPUS OF VITAMIN ADEFICIENTRATSNavigatore Fonzo LS, Delgado SM, Bonomi MR, Rezza IG, GimenezMS, Anzulovich AC.Lab Bioquímica Molecular, FQByF, UNSL, San Luis. E-mail:acanzu@unsl.edu.arThis work was 80% supported by NIH Res.Grant R01-TW006974funded by the FIC, USA.High levels of oxidative stress and alterations in the antioxidantdefense system lead to a deficit in cognitive function. Circadianexpression of GPx and CAT has been reported in different tissues.Our objective was to investigate the daily variation in protein levelsand activity of GPx and CAT and lipoperoxidation in thehippocampus of control, vitamin A-deficient and vitamin Arecoveredrats. GPx and CAT protein levels were determined byWestern blots. Their activities were measured following Flohe &Gunzler (1984) and Aebi (1984), respectively. MDA levelsfollowing Droper and Hadley (1990). We observed a rhythmicvariation in the antioxidant enzymes protein levels and activities,consistent with the circadian mRNA expression. Serum andhippocampus MDAlevels showed also a daily variation. VitaminAdeficiency modified the circadian pattern of GPx andCATand phaseshifted the daily variation of lipoperoxidation. Refeeding vitaminAdeficientrats with 15 days of control diet, led to a partial recoveringof antioxidant enzymes activities andMDAlevels. Daily variation inthe activity of the antioxidant defense system suggests that itscomponents are under biological clock-control and retinoids mighthave a role in the circadian regulation of cellular redox state andconsequently memory and learning.