Most people think of fat as stuff that just sits there – like the pendulous beer belly or the not so cute love handles. Scientists too have long thought of fat…and fat cells…as simply repositories of lipids (fats), which are storehouse material for energy that can be used by the body. Recent work, however, is showing fat cells to be more like an active organ of the body.

The new work is part of the growing field of proteomics, the study of proteins in their full relationship to other biological systems. Published in American Chemical Society (ACS) Journal of Proteome Research, the study [Identification of Novel Human Adipocyte Secreted Proteins by Using SGBS Cells] by Anja Rosenow, University of Maastricht (Netherlands) and other colleagues reveals that fat cells are part of the endocrine system and produce a variety of proteins as hormones.

Their research added 6 new proteins and 20 hormones (from a group known as adipokines) to the 80 proteins now known to be produced by fat cells. Although the biochemical pathways have not been fully established for these proteins, it is known that adipose (fat) cells play a role in the regulation (or deregulation) of the metabolism. Over the years virtually countless studies have linked obesity (too many fat cells) to a wide variety of illnesses including heart disease, diabetes, and cancer. This new research provides a different perspective to look at these links – fat cells as producers of regulatory and messaging hormones.

The picture that is emerging is of fat cells that are anything but passive repositories – they carry on a constant ‘conversation’ with other parts of the body in a system for managing the energy supply. When this system fails or behaves abnormally – as it does when people are obese – then many other systems are affected, leading in some cases to disease.