A Pilot Study to Investigate Circadian Variations in Brown Adipose Tissue Metabolism in Healthy Volunteers.
Brown adipose tissue is poorly understood fat that can metabolize glucose in order to generate heat. Since activated brown fat has a high metabolic rate, it is of great interest as a potential target to combat obesity. However, the signaling and control of brown fat metabolism is poorly understood. Because brown fat uses glucose as its energy source, brown fat metabolism can be imaged with PET/CT using the positron emitting glucose analog F-18 FDG. We have recently shown in mice a striking circadian variation in brown fat metabolism as evidenced by changes in FDG uptake. In this study we endeavor to generate pilot data on a potential circadian variation in brown fat activation in healthy humans.
• At least 18 years of age and less than 45 years of age
• Able and willing to provide informed consent
• Male gender
• Capable of complying with study procedures and able to lie still in the PET/CT scanner for up to 40 minutes continuously
• Normal fasting glucose (less than 100 mg/dl)
• No evidence of significant concurrent illness
• Follow typical sleep/wake cycle of generally asleep at night and awake during the day