Brown Adipose Tissue: A Metabolic Regulator in a Hypothalamic Cross Talk?

Since the discovery of functionally competent, energy-consuming brown adipose tissue (BAT) in adult humans, much effort has been devoted to exploring this tissue as a means for increasing energy expenditure to counteract obesity. However, despite promising effects on metabolic rate and insulin sensitivity, no convincing evidence for weight-loss effects of cold-activated human BAT exists to date. Indeed, increasing energy expenditure would naturally induce compensatory feedback mechanisms to defend body weight. Interestingly, BAT is regulated by multiple interactions with the hypothalamus from regions overlapping with centers for feeding behavior and metabolic control. Therefore, in the further exploration of BAT as a potential source of novel drug targets, we discuss the hypothalamic orchestration of BAT activity and the relatively unexplored BAT feedback mechanisms on neuronal regulation. With a holistic view on hypothalamic-BAT interactions, we aim to raise ideas and provide a new perspective on this circuit and highlight its clinical relevance.