Discovering The Developmental Origins of Obesity

The Polish Academy of Sciences in Olsztyn, Poland


Genetic variation in brown fat activity and body weight regulation in mice: Lessons for human studies

Leslie P. Kozak
Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, ul. Tuwima 10, Olsztyn 10-748, Poland

Diet induced obesity, Ucp1−/− mice, Brown adipose tissue and thermogenesis, aP2-Ucp1 transgenic mice, Allelic variation and Ucp1 expression, Muscle and diet-induced thermogenesis

The recent characterization of brown fat in humans has generated much excitement on the possibility that increased energy expenditure by heat production by this tissue will be able to reduce obesity. This expectation has largely been stimulated by studies with mice that show strong associations between increased brown fat activity and reductions in obesity and insulin resistance. Research in the mouse has been largely based upon the induction or suppression of brown fat andmitochondrial uncoupling protein by genetic methods.

The review of this research literature underscores the idea that reductions in obesity in mice are secondary to the primary role of brown adipose tissue in the regulation of body temperature. Given that the variation in brown fat in humans, as detected by PET imaging, is highly associated with administration of adrenergic agonists and reductions in ambient temperature, the effects on obesity in humans may also be secondary to the regulation of body temperature. Induction of thermogenesis by reduced ambient temperature now becomes like muscle and physical activity, another natural method of increased energy expenditure to combat obesity. Furthermore, there is no evidence to indicate that heat production by adrenergic stimulation via cold exposure or drug treatment or the enriched physical environment is restricted to the thermogenic activity of the brown adipocyte. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.