Metabolic adaptations of liver mitochondria during restricted feeding schedules

Abstract

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.

Quantification of Mitochondrial Acetylation Dynamics Highlights Prominent Sites of Metabolic Regulation

“…We detect increasing acetylation on seven lysines, with the greatest change on Lys-344, consistent with the known increase peroxisomal fatty oxidation (i.e. ␣-oxidation) in obesity (35,52). Overall, acetylation increases on most peroxisomal proteins in the obese state but decreases on most mitochondrial and endoplasmic reticulum proteins (Fig.…”

“…2B) (34). Rat liver Mdh2 activity is increased upon feeding (35), and previous studies have reported that Mdh2 activity can be increased either by acetylation (on Lys-185, Lys-301, Lys-307, and Lys-314) (36) or by Sirt3-dependent deacetylation (of Lys-239) (18). Here, we detect a large decrease in acetylation occupancy of Mdh2 Lys-239 with little or no changes to the other sites.…”

Pair feeding-mediated changes in metabolism: stress response and pathophysiology in insulin-resistant, atherosclerosis-prone JCR:LA-cp rats

“…In contrast to overt food restriction employed in other studies (5,15,28,50), there was no reduction in total caloric intake and therefore only a modest, albeit important, effect on body weight of adolescent animals, with no effect in mature rats (Fig. 1).…”

Effects of spaced feeding on gene expression of hepatic transaminase and gluconeogenic enzymes in rats

“…In the present study, we investigated the relationships between activity and gene expression of hepatic transaminases and the state of hepatic amino acid/glucose/ fatty acid metabolism. As daytime SF animals with caloric or dietary restriction are well known to show some characteristic adaptive changes in energy metabolism, glucose synthesis and fatty acid oxidation, a daytime spaced feeding model was employed to investigate the relationships (Báez-Ruiz et al, 2005;Leveille and Chakrabarty, 1968;Satoh et al, 2006;Wu et al, 2008). A 4-hr feeding condition in the light phase was employed in the present study because daytime 4-hr fed rats which were trained for 2 weeks consumed a diet of almost the same amount as that the ALF rats consumed in a day in our preliminary studies (data not shown).…”

“…As daytime SF animals with dietary restriction are well known to show some characteristic adaptive changes in energy metabolism, glucose synthesis and fatty acid oxidation associated with the shift of the animal's circadian rhythms (Báez-Ruiz et al, 2005;Leveille and Chakrabarty, 1968;Satoh et al, 2006;Wu et al, 2008), a daytime spaced feeding model was employed. Confirmation of the resetting of hepatic clock gene expression is useful to ensure the alteration of nutritional state of the SF rats including the alteration of the state of hepatic glucose metabolism because the expression of the hepatic clock gene is entrained by food stimuli such as spaced feeding (Satoh et al, 2006;Stokkan, 2001;Wu et al, 2008).…”