GSH reductase expression is circadian in the hippocampus and dampened in the vitamin A deficiency.

NAVIGATORE FONZO L; DELGADO S.M; GIMENEZ, M S; ANZULOVICH, AC

Potrero de los Funes, San Luis

Congreso; XLVII Reunión Anual de la Sociedad Argentina de investigación Bioquímica y Biología Molecular; 2011

Sociedad Argentina de investigación Bioquímica y Biología Molecular

Reduced glutathione (GSH) is the major endogenous antioxidant produced by cells and is critical for the maintenance of the redox potential in the brain. Our objectives were to investigate whether GSH reductase (GR) displays a circadian expression pattern in the rat hippocampus and to evaluate to which extent vitamin A deficiency (VAD) could modify temporal patterns of clock, RARs and GR expression. Holtzman rats weaned at 21 d of age were immediately assigned to either a vitamin A-free diet (DE group) or the same diet containing 4000 IU of vitamin A/Kg diet (CO group) during 3 months. Both groups were maintained under 12h- Light:12h-Dark or 12h-Dark:12h-Dark conditions during 10 days before the experiment. Hippocampi were taken every 4 h. GR transcript levels were determined by RT-PCR. RARa, RARß, BMAL1 and PER1 protein levels were determined by immunoblotting. We found mRNA levels of GR display a circadian pattern in the rat hippocampus peaking at the middle of the night (P<0.01). RARa, RARß, BMAL1 and PER1 also exhibited circadian rhythmicity (P< 0.05, P<0.01) in this brain area. VAD dampened the oscillating GR expression and phase shifted rhythms of clock and RARs proteins.Thus, VAD might affect the circadian expression of GR and consequently, the availability of GSH at a given time during the day, probably, by altering the circadian patterns of key clock and RARs proteins.a, RARß, BMAL1 and PER1 protein levels were determined by immunoblotting. We found mRNA levels of GR display a circadian pattern in the rat hippocampus peaking at the middle of the night (P<0.01). RARa, RARß, BMAL1 and PER1 also exhibited circadian rhythmicity (P< 0.05, P<0.01) in this brain area. VAD dampened the oscillating GR expression and phase shifted rhythms of clock and RARs proteins.Thus, VAD might affect the circadian expression of GR and consequently, the availability of GSH at a given time during the day, probably, by altering the circadian patterns of key clock and RARs proteins.a, RARß, BMAL1 and PER1 also exhibited circadian rhythmicity (P< 0.05, P<0.01) in this brain area. VAD dampened the oscillating GR expression and phase shifted rhythms of clock and RARs proteins.Thus, VAD might affect the circadian expression of GR and consequently, the availability of GSH at a given time during the day, probably, by altering the circadian patterns of key clock and RARs proteins.