Endogenous rhytthms of antioxidant enzymes in hippocampus are modified by the vitamin A deficiency

NAVIGATORE FONZO, L; RANDAZZO G; GIMENEZ, M S; ANZULOVICH, AC

Congreso; XLVI Reunión Anual de la Sociedad Argentina de investigación Bioquímica y Biología Molecular (SAIB; 2010

Sociedad Argentina de investigación Bioquímica y Biología Molecular

Daily profiles of GPx and CAT have been reported in different tissues. Some evidence points out retinoids as regulators of clock genes activity through its RAR and RXR receptors. Our objectives were to investigate whether GPx, CAT, and clock genes display a circadian expression pattern in the rat hippocampus and evaluate to which extent vitamin A deficiency (VAD) could modify the circadian profiles of Bmal1, Per1, CAT and GPx in that brain area. Male Holtzman rats from control and vitamin A-deficient groups were maintained under 12h-Light:12h-Dark or 12h-Dark:12h-Dark conditions during 10 days before the experiment. Rest-activity cycles were registered using the Archron system. Hippocampi were taken every 4 or 5 h. Transcript levels of Bmal1, Per1, CAT and GPx were determined by RT-PCR and protein levels by Western blot. Regulatory regions of CAT and GPx genes were scanned for clockand r e t inoid- r e spons ive s i t e s us ing Ma t Inspe c tor (www.genomatix.de). E-box and RARE sites were found on regulatory regions of GPx and CAT genes, which display an endogenously-controlled circadian expression in the rat hippocampus. VAD reduced the nocturnal activity of the rats and modified the circadian rhythmicity of CAT and GPx, probably, by altering BMAL1 and PER1 oscillation.