RT Journal A1 Elmquist JK, Scherer PE T1 NEuroendocrine and endocrine pathways of obesity JF JAMA JO JAMA YR 2012 FD September 19 VO 308 IS 11 SP 1070 OP 1071 DO 10.1001/jama.2012.3209 UL http://dx.doi.org/10.1001/jama.2012.3209 AB At first sight, the adipocyte appears to be fully occupied by a droplet of fat. It is difficult even to see the nucleus or any other structure responsible for the metabolic activity of cells, let alone to suggest that the adipocyte is a professional secretory cell. This benign appearance misled investigators for decades into believing that fat cells were passive storage organs that simply esterify dietary lipids upon consumption of a meal and release free fatty acids upon fasting. Over the past decade, it has become apparent that fat cells are metabolically much more active than anticipated. While the role of the adipocyte in postprandial glucose disposal is well understood, its roles in lipogenesis, glyceroneogenesis, and mitochondrial beta oxidation are increasingly appreciated. Adipose tissue is an important endocrine tissue intricately involved in the regulation of energy balance, as well as in the pathogenesis of diabetes, cardiovascular disease, and cancer, through its ability to sequester potentially toxic lipid species and to secrete a vast array of lipid and hormonal products (referred to as adipokines). This week’s cover and cover story figure feature the special role of adipose tissue among the complex relationships involved in the network of energy balance.