The secret life of fat cells

Abstract

The first evidence that fat cells have a role beyond storing energy from excess food came from a strain of massively obese mutant mice. Before these mice, some researchers had suspected the cells were more than just a calorie cache. After all, obesity increases a person’s risk of type 2 diabetes, liver disease, high blood pressure, arthritis, and more. If an increase in fat mass is one of the greatest risk factors for these conditions, surely the cells that store that fat aren’t just innocent bystanders. But it wasn’t until 1994, after years of sleuthing, that Jeffrey M. Friedman of Rockefeller University found definitive proof of fat cells’ secret lives: Those rotund mice were missing a peptide hormone named leptin (Nature 1994, DOI: 10.1038/372425a0). And that hormone was secreted by fat cells, also known as adipose cells. Without leptin to regulate their appetite, the animals were ravenous—and consequently grew nearly