Submitted to: Obesity Reviews
Publication Type: Review Article
Publication Acceptance Date: 4/27/2006
Publication Date: 2/10/2007
Citation: Bray, M.S., Young, M.E. 2006. Circadian rhythms in the development of obesity: Potential role for the circadian clock within the adipocyte. Obesity Reviews. 8(2):169-181. Interpretive Summary: Circadian rhythms are an important part of life. The circadian clock is composed of genes that turn themselves and each other on and off in a rhythmic manner. This review paper describes how these genes may promote the development of excess fat when they are not functioning properly.
Technical Abstract: Obesity is one of the most profound public health problems today, and simplistic explanations based on excessive nutritional consumption or lack of physical activity are inadequate to account for this dramatic and literal growth in our world population. Recent reports have suggested that disruptions in sleep patterns, often linked to our "24-h" lifestyle, are associated with increased body fat and altered metabolism, although the cause–effect relationship for these associations has yet to be elucidated. Abnormal sleep/wake patterns likely alter intra-cellular circadian clocks, which are molecular mechanisms that enable the cell/tissue/organism to anticipate diurnal variations in its environment. The environment may include circulating levels of nutrients (e.g., glucose, fatty acids and triglycerides) and various hormones (e.g., insulin, glucocorticoids). As such, alterations in this molecular mechanism, in particular within the adipocyte, likely induce metabolic changes that may potentiate disrupted metabolism, adipose accumulation, and/or obesity. Although diurnal variations in adipokines and adipose tissue metabolism have been observed, little is known regarding the molecular mechanisms that influence these events.