ABSTRACT
W e are currently undergoing a revolution in our perspectives on the physiological role of white adipose tissue (WAT). Traditionally, white fat has been viewed primarily as a long-term energy storage organ. The deposition of triacylglycerol with twice the energy density of carbohydrate and with little associated water (in the region of 15%) provides a concentrated and highly efficient energy reserve. The central role of WAT in the storage of lipid has resulted in lipogenesis and lipolvsis being viewed as the major metabolic processes associated with the organ, and much is known about the nature and regulation of these pathways. A second role widely attributed to WAT, at least for the subcutaneous deposits, is that of thermal insulation and in the case of the blubber of aquatic mammals such as whales the tissue may even have a mechanical role. Brown fat, the other form of adipose tissue, has the generation of heat, both thermoregulatory and in relation to the regulation of energy balance, as its primary function (see Chapters 4 and 5 bv Klaus).
