Central control of brown adipose tissue.

Thermogenesis is a term which can be used to describe any form of heat production, but is normally applied to adaptive or regulatory components of metabolic rate, namely non-shivering thermogenesis (NST) and diet-induced thermogenesis (DIT). NST and DIT are activated in response to physiological stimuli and are largely dependent on sympathetic activation of heat production in brown adipose tissue (BAT). The quantitative importance and thermogenic mechanisms of BAT will be reviewed by others participating in this symposium. The objective of the present review is to discuss our current knowledge of the central mechanisms involved in the control of BAT thermogenesis, and how they are affected by physiological or pathological conditions. Of all aspects of BAT thermogenesis it is the central control which is probably the least understood, partly as a result of its complexity, but also because it has received relatively little direct attention. Considerable information and insight into this area can, however, be gained from studies concerned with feeding behaviour and temperature regulation, both of which are closely related and show many common features with sympatheticallymediated thermogenesis. Over the past few years, our understanding of central thermogenic mechanisms has improved considerably, due mainly to studies specifically designed to investigate this problem.