ABSTRACT

B rown adipose tissue (BAT) is a specialized thermogenic adipose tissue with great importance for thermoregulation and cold defense of small mammals. As outlined in the previous chapter, the thermogenic function of BAT is intrinsically associated with the uncoupling of the mitochondrial respiratory chain by the uncoupling protein 1 (UCP 1 ) which is unique for brown adipocytes. In the '70's and '80's research was primarily focused on the biochemical mechanisms of BAT thermogenesis and its physiological regulation. The find­ ing that BAT thermogenesis can also be activated after excess dietary energy intake has en­ hanced research efforts especially from the obesity field. The last decade has witnessed enor­ mous progress in molecular biology techniques including transgenic animals. The availability of brown preadipocyte cell culture systems and increasing numbers of transgenic animal mod­ els with altered BAT function have contributed much to our current knowledge on molecular mechanisms of brown fat function and its role in energy homeostasis.