Regulation of lipolysis in adipose tissue.

The normal human or animal has a series of finely coordinated and overlapping control mechanisms that regulate the storage or release of fat according to the overall energy requirements of the body. We have examined only one side of this system, the part responsible for the release of fatty acids from adipose tissue. Considerable information is available on the extracellular factors that control lipolysis on a minute-to-minute or day-to-day basis, but less is known about long-term regulation or about the precise role of intracellular factors that almost surely condition the response of the fat cell to external stimuli. When one poses the question of what determines the overall fat mass or adiposity of an individual, even less is known. Psychogenic factors regulating food intake, circulating hormonal signals, and local regulators of metabolism in the adipose tissue may all play a role. This remains an intriguing but elusive problem to be answered by future research.