Jeffrey M. Friedman

Professor Friedman investigates the physiologic and neural mechanisms that regulate food intake and body weight. In 1994, Professor Friedman and his colleagues successfully cloned the gene responsible for the obesity in the mice, naming it the ob gene. His team found that the ob gene encoded a previously unknown protein, a hormone produced by fat cells, which they named leptin. In a groundbreaking experiment, they showed that injecting leptin into the obese mice caused them to lose weight by decreasing their food intake and increasing their energy expenditure. Professor Friedman's work demonstrated that leptin is a key afferent signal in a feedback loop that helps maintain a homeostatic body weight. His findings proved that obesity was not just a matter of willpower and opened an entirely new field of research into the biological causes of obesity. His discovery led to a transformative treatment for humans with a genetic leptin deficiency, who can be treated with leptin replacement therapy.