Leptin: the new gut buster?

Forget about liposuction. New research suggests that the cure for a tubby tummy may be leptin, a hormone thought to play a role in regulating body fat.

Researchers have been racing to unlock leptin's secrets since its discovery in 1994 (SN: 12/3/94, p. 372). Now, endocrinologist Luciano Rossetti of the Albert Einstein College of Medicine in New York and his colleagues have published a study of rats that suggests leptin may play a role in diseases associated with a fat abdomen, the spare tire that many people develop as they grow older.

Rossetti's team gave moderately obese rats an infusion of leptin for 8 days. As expected, the rats ate less and lost weight. However, the animals lost more fat from their abdomens than from other parts of their bodies. "That was a pretty striking phenomenon," Rossetti told Science News.

People with an apple-shaped body, in which fat is deposited mostly around the waist instead of on the thighs or hips, are known to run a greater risk of insulin resistance, a condition in which cells don't respond effectively to insulin's message to take up sugar from the bloodstream. People with insulin resistance, in turn, run a greater risk of developing diabetes.

In Rossetti's study, leptin significantly enhanced the effects of insulin. That finding raises the hope that leptin may help reverse insulin resistance in people and help ward off diabetes.

A potbelly is also associated with a greater risk of developing heart disease. Rossetti wonders if leptin, by selectively removing tummy fat, might ratchet down that risk as well. The team details its findings in the Dec. 15 Journal of Clinical Investigation.