Báez-Ruiz Adrián, Escobar Carolina, Aguilar-Roblero Raúl, Vázquez-Martínez Olivia, Díaz-Muñoz Mauricio
Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México-Juriquilla, Querétaro, Qro 76001, México.
Am J Physiol Gastrointest Liver Physiol. 2005 Dec;289(6):G1015-23. doi: 10.1152/ajpgi.00488.2004. Epub 2005 Jun 23.
Food anticipatory activity (FAA) is an output of the food-entrained oscillator (FEO), a conspicuous biological clock that expresses when experimental animals are under a restricted food schedule (RFS). We have shown that the liver is entrained by RFS and exhibits an anticipatory response before meal time in its oxidative and energetic state. The present study was designed to determine the mitochondrial oxidative and phosphorylating capacity in the liver of rats under RFS to further support the biochemical anticipatory role that this organ plays during the food entrainment (9). Metabolic and functional parameters of liver mitochondria were characterized before (0800 h), during (1100 h), and after (1400 h) FAA. The main results were as follows. First, there was an enhancement during FAA (1100 h) in 1) oxidative capacity (site I of the electron transport chain), 2) phosphorylating ability (estimated by ATP synthesis), and 3) activities of NADH shuttles. Second, after rats were fed (1400 h), the phosphorylating capacity remained high, but this was not the case for the respiratory control ratio for site I. Finally, in the three experimental conditions before, during, and after FAA, an increment was detected in the H(+) electrochemical potential, due to an elevation in mitochondrial membrane potential, and in mitochondrial yield. Most of the changes in mitochondrial properties related to RFS were also present when results were compared with those from the 24-h fasted group. In conclusion, the results support the notion that a distinctive rheostatic state is installed in the metabolic activity of the liver when FEO is being expressed.
食物预期活动（FAA）是食物诱导振荡器（FEO）的一种输出，FEO是一种显著的生物钟，在实验动物处于限时进食时间表（RFS）时表达。我们已经表明，肝脏被RFS所诱导，并且在进食时间之前，其氧化和能量状态会表现出预期反应。本研究旨在确定RFS条件下大鼠肝脏中的线粒体氧化和磷酸化能力，以进一步支持该器官在食物诱导过程中所起的生化预期作用（9）。在FAA之前（08:00）、期间（11:00）和之后（14:00）对肝脏线粒体的代谢和功能参数进行了表征。主要结果如下。首先，在FAA期间（11:00），1）氧化能力（电子传递链的位点I）、2）磷酸化能力（通过ATP合成估计）和3）NADH穿梭体的活性均有所增强。其次，在大鼠进食后（14:00），磷酸化能力仍然很高，但位点I的呼吸控制率并非如此。最后，在FAA之前、期间和之后的三种实验条件下，由于线粒体膜电位的升高和线粒体产量的增加，检测到H(+)电化学势有所增加。当将结果与24小时禁食组的结果进行比较时，与RFS相关的线粒体特性的大多数变化也存在。总之，这些结果支持了这样一种观点，即当FEO表达时，肝脏的代谢活动中会建立一种独特的稳流状态。
