Molecular and biochemical modifications of liver glutamine synthetase elicited by daytime restricted feeding
Por:
Vazquez-Martinez, O, De Ita-Perez, D, Valdes-Fuentes, M, Flores-Vidrio, A, Vera-Rivera, G, Miranda, MI, Mendez, I, Diaz-Munoz, M
Publicada:
1 oct 2014
Categoría:
Hepatology
Resumen:
Background & AimsThe circadian clock system in the liver plays
important roles in regulating metabolism and energy homeostasis.
Restricted feeding schedules (RFS) become an entraining stimulus that
promotes adaptations that form part of an alternative circadian clock
known as the food entrained oscillator (FEO). The aim of this study was
to evaluate the daily variations of glutamine synthetase (GS) in liver
under a daytime RFS.
MethodsHepatic GS properties were analysed at 3-h intervals over a 24-h
period in adult male Wistar rats maintained in a 12:12h light-dark
cycle. RFS group: food access for 2-h in light phase, during 3weeks. AL
group: feeding ad libitum. Fa group: acute fast (21h). Fa-Re group:
acute fast followed by refed 2h. mRNA expression was measured by
RT-qPCR, protein presence by Western-blot and immunohistochemistry,
enzyme activity by a spectrophotometric assay, and glutamine by high
pressure liquid chromatography.
Results and ConclusionsRestricted feeding schedule induced circadian
rhythmicity in mRNA levels of GS and the loss of the rhythmic pattern in
mitochondrial GS activity. GS activity in liver homogenates displayed a
robust rhythmic pattern in AL that was not modified by RFS. The presence
of GS and its zonal distribution did not show rhythmic pattern in both
groups. However, acute Fa and Fa-Re diminished GS protein and activity
in liver homogenates. Hepatic glutamine concentrations showed a 24-h
rhythmic pattern in both groups, in an antiphasic pattern. In
conclusion, daytime RFS influences the liver GS system at different
levels, that could be part of rheostatic adaptations associated to the
FEO, and highlight the plasticity of this system.
Filiaciones:
Vazquez-Martinez, O:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Dept Cellular & Mol Neurobiol, Queretaro 76230, Qro, Mexico
De Ita-Perez, D:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Dept Cellular & Mol Neurobiol, Queretaro 76230, Qro, Mexico
Valdes-Fuentes, M:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Dept Cellular & Mol Neurobiol, Queretaro 76230, Qro, Mexico
Flores-Vidrio, A:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Dept Cellular & Mol Neurobiol, Queretaro 76230, Qro, Mexico
Vera-Rivera, G:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Dept Behav & Cognit Neurobiol, Queretaro 76230, Qro, Mexico
Miranda, MI:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Dept Behav & Cognit Neurobiol, Queretaro 76230, Qro, Mexico
Mendez, I:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Dept Cellular & Mol Neurobiol, Queretaro 76230, Qro, Mexico
Diaz-Munoz, M:
Univ Nacl Autonoma Mexico, Inst Neurobiol, Dept Cellular & Mol Neurobiol, Queretaro 76230, Qro, Mexico
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