ABSTRACT
This chapter discusses species distribution of brown adipose tissue (BAT), using biochemical criteria for its identification. Although BAT has long been recognized in small rodents, the extent to which it occurs in other - especially larger - species has been unclear. This uncertainty is principally a consequence of the absence of a satisfactory basis for the identification of BAT, and specifically its differentiation from white fat. The immunological identification of Uncoupling protein (UCP) in mitochondria provides a powerful tool for the characterization of adipose tissues, an approach that has been used in the search for BAT in a wide range of mammals. There has been some interest in whether BAT is present in marsupials, and mitochondrial GDP binding studies with Bennets' wallaby have suggested that this may indeed be the case. The mRNA for UCP has been detected by Northern blotting in a range of mammals, using either a cDNA probe or the 27-mer oligonucleotide.
