The effect of low environmental temperature on the composition of depot fat in relation to hibernation

Fawcett, Don W.; Lyman, Charles P.

doi:10.1113/jphysiol.1954.sp005205

Cited by 145 publications

(12 citation statements)

References 17 publications

(23 reference statements)

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“…This is consistent with the findings of Wells et al (1965) for brown fat of non-hibernating M. l. lucifugus and Paulsrud and Dryer (1968) for brown fat of E. fuscus entering hibernation. A high level of unsaturated fatty acids is a common occurrence in animals preparing for hibernation and appears to be related to a lowering of the environmental temperature (Fawcett & Lyman, 1954). A high content of palmitoleic acid occurred in each species in our study.…”

Section: Lipid Analysissupporting

confidence: 51%

Autumn fat deposition and gross body composition in three species of Myotis

Ewing

Studier

O’Farrell

1970

Comparative Biochemistry and Physiology

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Abstract--1. Mid-August to mid-September fat indices for female Myotis lucifugus were 0.58-0"69 g fat/g lean dry wt. with constant gross body composition.2. During the same time span, fat indices of female M. yumanensis showed a gradual significant increase from 0"30 to 0"87 with a concurrent significant increase in percent non-fat and percent water.3. In mid-September, fat indices of M. thysanodes increased significantly from 0'09 to 0-73, while gross body composition was unchanged.4. M. thysanodes body fat had a caloric content of 9"418 + 0"016 kcal/g. 5.Fatty acid analysis revealed 72-81 per cent unsaturation with oleic acid being the most abundant.6. For each species, females contained more body fat than males, and adults were fatter than young of the year.

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Section: Lipid Analysissupporting

confidence: 51%

Autumn fat deposition and gross body composition in three species of Myotis

Ewing

Studier

O’Farrell

1970

Comparative Biochemistry and Physiology

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“…Additionally, several auxiliary enzymes, which are required for the ␤-oxidation of unsaturated fatty acids, are increased including DECR2 and ECH1. This correlates with increased unsaturated fatty acids found in fat depots in thirteen-lined ground squirrels (28). In addition to increased ␤-oxidation of fatty acids in the peroxisome during hibernation, we also see increased expression of genes associated with ␣-oxidation of fatty acids, including the lyase HACL1.…”

Section: Functional Analysismentioning

confidence: 55%

“…Additionally, enhanced calcium handling in the heart provides a more efficient way to clear cytosolic calcium stores and thus preventing calcium overload, which occurs in nonhibernators at reduced temperatures (10,17,63,103,107). Others attribute the cold resistance to the hibernator's ability to decrease saturation of depot fats, making these lipids available for fuel utilization throughout the hibernation season (28). Moreover, optimal cardiac function is thought to be maintained by increased rates and efficiency of energy production and utilization in the cardiac tissue, including altered enzyme functionality and alternate metabolic pathway utilization (13,54).…”

mentioning

confidence: 99%

Gene expression changes controlling distinct adaptations in the heart and skeletal muscle of a hibernating mammal

Vermillion

Anderson

Hampton

et al. 2015

Physiological Genomics

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Throughout the hibernation season, the thirteen-lined ground squirrel ( Ictidomys tridecemlineatus) experiences extreme fluctuations in heart rate, metabolism, oxygen consumption, and body temperature, along with prolonged fasting and immobility. These conditions necessitate different functional requirements for the heart, which maintains contractile function throughout hibernation, and the skeletal muscle, which remains largely inactive. The adaptations used to maintain these contractile organs under such variable conditions serves as a natural model to study a variety of medically relevant conditions including heart failure and disuse atrophy. To better understand how two different muscle tissues maintain function throughout the extreme fluctuations of hibernation we performed Illumina HiSeq 2000 sequencing of cDNAs to compare the transcriptome of heart and skeletal muscle across the circannual cycle. This analysis resulted in the identification of 1,076 and 1,466 differentially expressed genes in heart and skeletal muscle, respectively. In both heart and skeletal muscle we identified a distinct cold-tolerant mechanism utilizing peroxisomal metabolism to make use of elevated levels of unsaturated depot fats. The skeletal muscle transcriptome also shows an early increase in oxidative capacity necessary for the altered fuel utilization and increased oxygen demand of shivering. Expression of the fetal gene expression profile is used to maintain cardiac tissue, either through increasing myocyte size or proliferation of resident cardiomyocytes, while skeletal muscle function and mass are protected through transcriptional regulation of pathways involved in protein turnover. This study provides insight into how two functionally distinct muscles maintain function under the extreme conditions of mammalian hibernation.

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“…Seasonally hibernating ground squirrels and woodchucks fatten markedly prior to hibernation and may more than double their weight in the autumn months. Hamsters change the saturation of their depot fat when exposed to cold (Fawcett and Lyman, 1954) and tend not to hibernate when denied the ability to store food (Lyman, 1954). In many species which hibernate, a polyglandular involution of the endocrines during the autumn has been observed, but its causal relationship to hibernation has not been proved and hibernation has not been induced by abolition of any of the endocrine organs (Popovic, 1960a).…”

Section: Introductionmentioning

confidence: 99%

Circulation in Mammalian Hibernation

Lyman¹

1962

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The effect of low environmental temperature on the composition of depot fat in relation to hibernation

Cited by 145 publications

References 17 publications

Autumn fat deposition and gross body composition in three species of Myotis

Autumn fat deposition and gross body composition in three species of Myotis

Gene expression changes controlling distinct adaptations in the heart and skeletal muscle of a hibernating mammal

Circulation in Mammalian Hibernation

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