Tumour necrosis factor-alpha (TNF) is a pleiotropic cytokine involved in many 
metabolic responses in both normal and pathophysiological states. In spite of 
the fact that this cytokine (also known as "cachectin") has been related to many 
of the metabolic abnormalities associated with cachexia, recent studies suggest 
that TNF may also have a central role in obesity modulating energy expenditure, 
fat deposition and insulin resistance. This review deals with the role of TNF in 
the control of fat mass and obesity.