Brown adipose tissue lipid is the main source of energy during arousal of the golden hamster (Mesocricetus auratus)

The effect of fasting on sympathetic activity in tissues of the golden hamster has been investigated using measurements of noradrenaline turnover. Fasting for 60 h did not have a significant effect on noradrenaline turnover, both fractional and total, in brown adipose tissue or the heart. Fasting did, however, result in a functional atrophy of brown adipose tissue; tissue weight, protein content, and cytochrome oxidase activity were each reduced after a 60-h fast. These results suggest that the atrophy of brown adipose tissue induced by fasting in the golden hamster does not relate to a major decrease in sympathetic activity. The findings add further support for the view that the thermogenic capacity of brown adipose tissue is not primarily dependent on sympathetic activity in the golden hamster.

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Cold exposure induces dynamic, heterogeneous alterations in human brown adipose tissue lipid content

Scientific Reports ◽

10.1038/s41598-019-49936-x ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 5

Author(s):

Crystal L. Coolbaugh ◽

Bruce M. Damon ◽

Emily C. Bush ◽

E. Brian Welch ◽

Theodore F. Towse

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Lipid Content ◽

Cold Exposure ◽

Simultaneous Increase ◽

Tissue Lipid ◽

Resonance Imaging ◽

Initial Value ◽

Brown Adipose ◽

Simultaneous Synthesis

Abstract Brown adipose tissue undergoes a dynamic, heterogeneous response to cold exposure that can include the simultaneous synthesis, uptake, and oxidation of fatty acids. The purpose of this work was to quantify these changes in brown adipose tissue lipid content (fat-signal fraction (FSF)) using fat-water magnetic resonance imaging during individualized cooling to 3 °C above a participant’s shiver threshold. Eight healthy men completed familiarization, perception-based cooling, and MRI-cooling visits. FSF maps of the supraclavicular region were acquired in thermoneutrality and during cooling (59.5 ± 6.5 min). Brown adipose tissue regions of interest were defined, and voxels were grouped into FSF decades (0–10%, 10–20%…90–100%) according to their initial value. Brown adipose tissue contained a heterogeneous morphology of lipid content. Voxels with initial FSF values of 60–100% (P < 0.05) exhibited a significant decrease in FSF while a simultaneous increase in FSF occurred in voxels with initial FSF values of 0–30% (P < 0.05). These data suggest that in healthy young men, cold exposure elicits a dynamic and heterogeneous response in brown adipose tissue, with areas initially rich with lipid undergoing net lipid loss and areas of low initial lipid undergoing a net lipid accumulation.

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Thermogenic activity and capacity of brown fat in fasted and refed golden hamsters

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1987.252.5.r987 ◽

1987 ◽

Vol 252 (5) ◽

pp. R987-R993 ◽

Cited By ~ 3

Author(s):

I. Levin ◽

P. Trayhurn

Keyword(s):

Adipose Tissue ◽

Cytochrome C ◽

Brown Adipose Tissue ◽

Cytochrome C Oxidase ◽

Golden Hamster ◽

Oxidase Activity ◽

Uncoupling Protein ◽

Mitochondrial Mass ◽

Brown Adipose ◽

Brown Adipose Tissue Thermogenesis

The effects of different food deprivation regimens on the thermogenic activity and capacity of brown adipose tissue in the golden hamster have been investigated. Thermogenesis in the tissue was assessed by measurements of tissue cytochrome-c oxidase activity, mitochondrial GDP binding, and the specific mitochondrial concentration of uncoupling protein. The thermogenic activity and capacity of brown adipose tissue were found to be markedly reduced in fasted or underweight hamsters. Measurements of cytochrome-c oxidase activity indicate that the reductions were caused exclusively by a loss in mitochondrial mass, uncoupling protein concentration and GDP binding to mitochondria remaining unchanged. The decrease in brown adipose tissue thermogenesis was associated with a reduction in the capacity for nonshivering thermogenesis in the whole animal. Hamsters recovered from weight losses without increasing their food intake, and the recovery was accompanied by a normalization in mitochondrial mass in brown adipose tissue. Mitochondrial mass was, however, restored only after 10 days of ad libitum refeeding. These results suggest that the reduction in energy expenditure in the fasted hamster could relate to a decrease in brown adipose tissue thermogenesis, in addition to the previously reported decreases in resting metabolic rate and locomotor activity. Reductions in thermogenesis may also represent a further mechanism by which energy stores recover in the golden hamster without postfast hyperphagia.

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