Resistance to Hormone Leptin Called Key to Obesity
(HealthDay News, 3/7/07)

Normally leptin, a hormone secreted by fat cells, binds to neurons in the brain’s hypothalamus region and controls appetite and the use of stored energy; however, obese people tend to be resistant to leptin. Michael Cowley, of Oregon Health and Science University, and team, studied the biochemical mechanism of leptin-resistance by feeding mice a high-fat diet for 20 weeks, resulting in a 65% obesity rate. The researchers then compared the obese mice to their lean littermates and to control mice fed a normal diet. The scientists found that leptin did not trigger a response in the neurons of the obese mice, but once theseanimals were fed a low-fat diet, they recovered from leptin resistance, dropped weight and their responses returned to normal. These findings suggest that diet-induced weight loss can reverse leptin resistance, thereby restoring the mechanism that maintains normal weight.

(Cell Metabolism, March 2007)