H (2013) Circadian regulation of lipid mobilization in white adipose tissues

In mammals, a network of circadian clocks regulates 24-h rhythms of behavior and physiology. Circadian disruption pro-motes obesity and the development of obesity-associated disor-ders, 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, ClockD19, and Bmal12/2 circadian mutant mice were subjected to biochemical assays and gene ex-pression 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. Circa-dian clock mutant mice show low and nonrhythmic FFA and glyc-erol blood content together with decreased lipolysis rates an