Prehibernation and hibernation effects on the d-3-hydroxybutyrate dehydrogenase of the heavy and light mitochondria from liver jerboa (Jaculus orientalis) and related metabolism

Mountassif, Driss; Kabine, Mostafa; Latruffe, Norbert; Kebbaj, M'Hammed Saïd El

doi:10.1016/j.biochi.2007.04.001

Cited by 11 publications

(8 citation statements)

References 43 publications

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“…They may also play a role in combating oxidative stress during arousal when oxygen levels and oxygen consumption rise dramatically over short periods of time as animals power themselves back to euthermia by means of high rates of lipid-fueled thermogenesis in BAT and skeletal muscle. Indeed, recent studies have shown that elevated levels of biliverdin or bilirubin are associated with hibernation: plasma bilirubin rose 5-fold in torpid jerboas (Mountassif et al 2007), and bilirubin levels increased 5-fold in bile in hibernating ground squirrels (Baker and van Breukelen 2009). Compared with squirrels entering hibernation or in full torpor, biliverdin in ground squirrel liver was 15-to 20-fold higher both during arousal (Tb 20-25 8C) and during the interbout periods before animals re-entered torpor (>2 h at Tb >34 8C) (Nelson et al 2009).…”

Section: Discussionmentioning

confidence: 99%

Heme oxygenase expression and Nrf2 signaling during hibernation in ground squirrelsThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.

Storey

2010

Can. J. Physiol. Pharmacol.

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Mammalian hibernation is composed of long periods of deep torpor interspersed with brief periods of arousal in which the animals, fueled by high rates of oxygen-based thermogenesis in brown adipose tissue and skeletal muscle, power themselves back to euthermic (~37 degrees C) body temperatures. Strong antioxidant defences are important both for long-term cytoprotection during torpor and for coping with high rates of reactive oxygen species generated during arousal. The present study shows that the antioxidant enzyme heme oxygenase 1 (HO1) is strongly upregulated in selected organs of thirteen-lined ground squirrels (Spermophilus tridecemlineatus) during hibernation. Compared with euthermic controls, HO1 mRNA transcript levels were 1.4- to 3.8-fold higher in 5 organs of hibernating squirrels, whereas levels of the constitutive isozyme HO2 were unchanged. Similarly, HO1 protein levels increased by 1.5- to 2.0-fold in liver, kidney, heart, and brain during torpor. Strong increases in the levels of the Nrf2 transcription factor and its heterodimeric partner protein, MafG, in several tissues indicated the mechanism of activation of hibernation-responsive HO1 gene expression. Furthermore, subcellular distribution studies with liver showed increased nuclear translocation of both Nrf2 and MafG in torpid animals. The data are consistent with the suggestion that Nrf2-mediated upregulation of HO1 expression provides enhanced antioxidant defence to counter oxidative stress in hibernating squirrels during torpor and (or) arousal.

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Section: Discussionmentioning

confidence: 99%

Heme oxygenase expression and Nrf2 signaling during hibernation in ground squirrelsThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.

Storey

2010

Can. J. Physiol. Pharmacol.

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“…The rise in hepatic biliverdin levels in IBA squirrels may therefore reflect a burst of heme degradation as the liver is reperfused with blood upon arousal. Although there is little information on heme metabolism in hibernators, plasma bilirubin levels are elevated in torpid jerboas (35). Increased biliverdin during arousal may have functional significance beyond just heme catabolism.…”

Section: Discussionmentioning

confidence: 99%

Analysis of the hibernation cycle using LC-MS-based metabolomics in ground squirrel liver

Nelson

Otis

Martin

et al. 2009

Physiological Genomics

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A hallmark of hibernation in mammals is metabolic flexibility, which is typified by reversible bouts of metabolic depression (torpor) and the seasonal shift from predominantly carbohydrate to lipid metabolism from summer to winter. To provide new insight into the control and consequences of hibernation, we used LC/MS-based metabolomics to measure differences in small molecules in ground squirrel liver in five activity states: summer, entering torpor, late torpor, arousing from torpor, and interbout arousal. There were significant alterations both seasonally and within torpor-arousal cycles in enzyme cofactor metabolism, amino acid catabolism, and purine and pyrimidine metabolism, with observed metabolites reduced during torpor and increased upon arousal. Multiple lipids also changed, including 1-oleoyllysophosphatidylcholine, cholesterol sulfate, and sphingosine, which tended to be lowest during torpor, and hexadecanedioic acid, which accumulated during a torpor bout. The results reveal the dramatic alterations that occur in several classes of metabolites, highlighting the value of metabolomic analyses in deciphering the hibernation phenotype.

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“…It is well established that lipids play crucial roles in hibernation biology through their contribution to energy metabolism during the winter fast and their effects on membrane composition, which have been linked to torpor patterns [3], [4], [5], [6], [7]. Less well understood is the effect of hibernation on lipid trafficking, especially cholesterol and lipoprotein dynamics, over the annual cycle and its functional significance [8], [9], [10], [11].…”

Section: Introductionmentioning

confidence: 99%

Cholesterol and Lipoprotein Dynamics in a Hibernating Mammal

et al. 2011

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Hibernating mammals cease feeding during the winter and rely primarily on stored lipids to fuel alternating periods of torpor and arousal. How hibernators manage large fluxes of lipids and sterols over the annual hibernation cycle is poorly understood. The aim of this study was to investigate lipid and cholesterol transport and storage in ground squirrels studied in spring, summer, and several hibernation states. Cholesterol levels in total plasma, HDL and LDL particles were elevated in hibernators compared with spring or summer squirrels. Hibernation increased plasma apolipoprotein A-I expression and HDL particle size. Expression of cholesterol 7 alpha-hydroxylase was 13-fold lower in hibernators than in active season squirrels. Plasma triglycerides were reduced by fasting in spring but not summer squirrels. In hibernators plasma β-hydroxybutyrate was elevated during torpor whereas triglycerides were low relative to normothermic states. We conclude that the switch to a lipid-based metabolism during winter, coupled with reduced capacity to excrete cholesterol creates a closed system in which efficient use of lipoproteins is essential for survival.

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Prehibernation and hibernation effects on the d-3-hydroxybutyrate dehydrogenase of the heavy and light mitochondria from liver jerboa (Jaculus orientalis) and related metabolism

Cited by 11 publications

References 43 publications

Heme oxygenase expression and Nrf2 signaling during hibernation in ground squirrelsThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.

Heme oxygenase expression and Nrf2 signaling during hibernation in ground squirrelsThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.

Analysis of the hibernation cycle using LC-MS-based metabolomics in ground squirrel liver

Cholesterol and Lipoprotein Dynamics in a Hibernating Mammal

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