Turku PET Centre, Turku University Hospital and University of Turku, Turku, Finland
Institute of Public Health and Clinical Nutrition, University of Eastern Finland (UEF), Kuopio, Finland
Dr. Virtanen is one of the pioneers showing the existence of brown adipose tissue in adult humans in 2009. She has published several groundbreaking papers on human brown fat metabolism and its importance in human physiology. The interest in brown fat studies has focused on cold but also to other activators, such as hormones and their regulatory role in brown fat physiology in health and in obesity. Most recently, the studies have revealed new information on meal-induced changes in brown fat function. Currently, Kirsi Virtanen works in University of Eastern Finland.
The unique capacity of brown adipose tissue (BAT) to convert chemical substrate energy to heat is the key element of BAT activation. Cold-induced BAT metabolic is associated with increased whole body energy expenditure, indicating the active role of BAT in energy metabolism. Cold is highly potent activator of brown fat metabolism, but eating is as potent activator of brown fat oxidative metabolism. A carbohydrate-rich meal increases BAT metabolic oxidative metabolism as much as acute cold exposure. The role of gastro-intestinal hormones on brown fat metabolic function is under investigation. Insulin activates brown fat, and additionally secretin increases brown fat metabolic activity in healthy humans.