ENDOGENOUS RHYTHMS OF ANTIOXIDANT ENZYMES IN HIPPOCAMPUS ARE MODIFIED BY THE VITAMIN A DEFICIENCY

NAVIGATORE FONZO LS; RANDAZZO G; GIMENEZ MS; ANZULOVICH AC

Puerto Madryn

Congreso; 46th. Annual meeting SAIB; 2010

SAIB

Daily profiles of GPx and CAT have been reported in differenttissues. Some evidence points out retinoids as regulators of clockgenes activity through its RAR and RXR receptors. Our objectiveswere to investigate whether GPx, CAT, and clock genes display acircadian expression pattern in the rat hippocampus and evaluate towhich extent vitamin A deficiency (VAD) could modify thecircadian profiles of Bmal1, Per1, CAT and GPx in that brain area.Male Holtzman rats from control and vitamin A-deficient groupswere maintained under 12h-Light:12h-Dark or 12h-Dark:12h-Darkconditions during 10 days before the experiment. Rest-activitycycles were registered using the Archron system. Hippocampi weretaken every 4 or 5 h. Transcript levels of Bmal1, Per1, CAT and GPxwere determined by RT-PCR and protein levels by Western blot.Regulatory regions of CAT and GPx genes were scanned for clockandr 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 onregulatory regions of GPx and CAT genes, which display anendogenously-controlled circadian expression in the rathippocampus. VAD reduced the nocturnal activity of the rats andmodified the circadian rhythmicity of CAT and GPx, probably, byaltering BMAL1 and PER1 oscillation.Supported by NIH Grant R01-TW006974 funded by the FIC, USA.