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Diabetes. 2013 Jul;62(7):2195-203. doi: 10.2337/db12-1449. Epub 2013 Feb 22.

Circadian regulation of lipid mobilization in white adipose tissues.

Author information

1
Circadian Rhythms Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.

Abstract

In mammals, a network of circadian clocks regulates 24-h rhythms of behavior and physiology. Circadian disruption promotes obesity and the development of obesity-associated disorders, but it remains unclear to which extent peripheral tissue clocks contribute to this effect. To reveal the impact of the circadian timing system on lipid metabolism, blood and adipose tissue samples from wild-type, ClockΔ19, and Bmal1(-/-) circadian mutant mice were subjected to biochemical assays and gene expression profiling. We show diurnal variations in lipolysis rates and release of free fatty acids (FFAs) and glycerol into the blood correlating with rhythmic regulation of two genes encoding the lipolysis pacemaker enzymes, adipose triglyceride (TG) lipase and hormone-sensitive lipase, by self-sustained adipocyte clocks. Circadian clock mutant mice show low and nonrhythmic FFA and glycerol blood content together with decreased lipolysis rates and increased sensitivity to fasting. Instead circadian clock disruption promotes the accumulation of TGs in white adipose tissue (WAT), leading to increased adiposity and adipocyte hypertrophy. In summary, circadian modulation of lipolysis rates regulates the availability of lipid-derived energy during the day, suggesting a role for WAT clocks in the regulation of energy homeostasis.

PMID:
23434933
PMCID:
PMC3712056
DOI:
10.2337/db12-1449
[Indexed for MEDLINE]
Free PMC Article

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