title: Daily oscillation of glutathione redox cycle is dampened in the nutritional vitamin A deficiency.
abstract: Examples of hormonal phase-shifting of circadian gene expression began to emerge a few years ago. Vitamin A fulfills a hormonal function by binding of retinoic acid to its nuclear receptors, RARs and RXRs. We found retinoid- as well as clock-responsive sites on regulatory regions of Glutathione reductase (GR) and Glutathione peroxidase (GPx) genes. Interestingly, we observed retinoid receptors, as well as GSH, GR and GPx, display daily oscillating patterns in the rat liver. We also found that feeding animals with a vitamin A-free diet, dampened daily rhythms of RARα and RXRβ mRNA, GR expression and activity, GSH, BMAL1 protein levels and locomotor activity. Differently, day-night oscillations of RXRα, GPx mRNA levels and activity and PER1 protein levels, were phase-shifted in the liver of vitamin A-deficient rats. These observations would emphasize the importance of micronutrient vitamin A in the modulation of biological rhythms of GSH and cellular redox state in liver.
authors.affiliation: Laboratory of Chronobiology, Multidisciplinary Institute of Biological Research San Luis (IMIBIO-SL), National Council of Science and Technology (CONICET), National University of San Luis (UNSL). Chacabuco y Pedernera, D5700HHW, San Luis, Argentina.
authors.forename: Ivana Tamara
authors.initials: IT
authors.lastname: Ponce
authors.forename: Irma Gladys
authors.initials: IG
authors.lastname: Rezza
authors.forename: Silvia Marcela
authors.initials: SM
authors.lastname: Delgado
authors.forename: Lorena Silvina
authors.initials: LS
authors.lastname: Navigatore
authors.forename: Myrtha Ruth
authors.initials: MR
authors.lastname: Bonomi
authors.forename: Rebeca Laura
authors.initials: RL
authors.lastname: Golini
authors.forename: María Sofia
authors.initials: MS
authors.lastname: Gimenez
authors.forename: Ana Cecilia
authors.initials: AC
authors.lastname: Anzulovich