Figure 2. Adipocytes regulate energy balance by endocrine and non-endocrine mechanisms.
Adipocytes synthesize and secrete leptin, which circulates in the blood and acts on the CNS (primarily the hypothalamus) to reduce food intake and enhance energy expenditure. Adipose tissue also communicates with the CNS by means of a rich network of peripheral nerves, which can transmit afferent signals about energy status to the brain, such as when UCP-1 is expressed ectopically. This results in enhanced leptin sensitivity, which increases the effect of secreted leptin on energy balance.